As a writer of fantasy and a reader of everything under the sun, I think it goes without saying that I love fiction. And not only in books — I'm a sucker for movies too. In short, stories rule. But there's also no denying that they give us a pretty skewed picture of how the world works. And so, as a public service to fiction lovers everywhere, I give you … lies fiction tells us.

1. It will be easy to get what you want

My inspiration for this list came from an article by David Wong, author of John Dies at the End. In it, he observes that training montages and their ilk in films give us a false impression of how difficult it is to achieve anything. You start out with someone who's rubbish at something, insert a three-minute series of clips set to upbeat music, and bam! They're the world champion. Which means that anyone who sets out to do something and finds that it requires actual work winds up disappointed.

Thinking about this eminently valid point, I came to the conclusion that the problem actually goes deeper. The problem is narrative itself. Because although books and films may be brilliant at getting us into the heads of their protagonists, evoking what it's like to experience all kinds of extreme emotions and situations, one thing they're not very good at bringing alive is mind-numbingly dull repetition. A narrative, by its very nature, picks and chooses the key incidents that make up a coherent story. Everyday details — by which I mean the trivial stuff we literally do every day — are left out.

Of course that's the right thing to do, narratively speaking: if a book included every last thing its protagonist did then it would take as long to read as it would to actually live. But it means that processes like learning to be a chess grand master or bringing up a child, both of which inherently consist of doing the same damn tasks over and over and over, can never fully be represented in fiction. One or even a couple of instances of those tasks, yes, but in such cases the real experience comes from the cumulative effect of thousands of repeats. So basically, in contravention of the main tenet of modern fiction, this kind of thing can only really be told; it can't be shown. No wonder that when we walk away from the cinema, it's with the conviction that we too could become a world-class wrestler/musician/Jedi after five minutes' practice.

This lie is closely related to the more specific 'anything is possible if you believe in yourself', which conveniently ignores the rather large part played by talent and hard work — and brings me nicely to …

2. You will always get what you want

This is an even more fundamental issue than the last one. Because regardless of how easy or hard it is, fiction tells us that eventually We Will Succeed. Again, this is a problem built in to basic narrative convention. Most books and films have a protagonist. And most protagonists succeed. If they didn't, they wouldn't be the protagonist. No-one's interested in the story of the guy who didn't blow up the Death Star or the girl who didn't win the Hunger Games.

Of course, the problem with this from a real-life point of view is that we all think we're the protagonist. Our lives are being narrated from our own first-person viewpoint, so naturally we think we're bound to succeed in the end — 'cos that's what protagonists do. Sadly, however, as far as the universe is concerned, most of us are really just bit players. In the vast list of credits at the end of time, we'll appear as 'person in crowd, number 6 billion'.

Not only that, but life doesn't conform to a tidy narrative structure. So chances are, even if you do get what you want, that won't be the conclusion of your story. You'll get to experience the bit after THE END, where you trip over a printer cable and break your neck: a fate that doesn't even have the grace to be ironic/teach a moral lesson/say something profound about humanity.

And talking of moral lessons …

3. A near-tragedy can reform you overnight

This is a fictional staple. You know how it goes: a power-hungry city type nearly loses his family and — realising there's more to life than money — promptly quits his job to become a stay-at-home dad. Or a selfish hedonist receives devastating news of her brother's illness and instantly becomes a better person, dedicating her life to his care.

I'm not saying this kind of thing can't happen. But the truth is, change like this is rare. No single moment of revelation, however shocking or eye-opening, can balance out an entire lifetime of being the world's biggest bitch. What really tends to happen is that a person experiences the epiphany, resolves to be better, and keeps it up for a couple of days before gradually regressing into old habits. Because, let's face it, improving oneself is hard. And if you're the kind of person who's allowed yourself to get away with being ruthless or vindictive or self-obsessed for years then it's hardly going to be as easy as a snap of the fingers to change.

Yes, these 'defining moments' can cause us to take a long, hard look at ourselves, but there's still a helluva lot of work to do after that … which brings us back to Lie 1.

4. Creepy, obsessive and/or borderline stalker-ish behaviour is the way to win a heart

I can't help but think of the scene in Twilight where Edward freely confesses to Bella that he creeps into her room every night to watch her sleep. This is apparently romantic and not the kind of psychotic behaviour that should have any sensible girl straight on the phone to the police.

Fiction really doesn't do anyone any favours here. In real life, constantly pursuing someone even after they've said no is harrassment, not endearing dedication. Breaking into someone's apartment to strew it with flowers is less of a grand romantic gesture than a criminal offence. And contrary to the plot of almost every rom-com I can think of, dating someone because (a) you're a journalist writing an article or (b) you've made a bet with your friends that you can turn an ugly duckling into a swan is not going to end in a happy, long-term relationship.

Oh, and unless you're a class nerd who also happens to be the protagonist of a second-rate movie, you're not going to end up with the hottest, most popular kid in school. Deal with it.

5. Babies sleep all the time

Yeah. I got screwed over by that one.

I'm sure that all of you, my lovely readers and fellow writers, know how to use apostrophes correctly. But since I'm always being driven to distraction by their frequent misuse — in books, on signs, in promotional literature — I decided I'd write this: my potted guide to the apostrophe. If you know someone who struggles with the little blighters then why not print out a copy and staple it to their head … er, I mean tape it to their computer screen.

The first thing you need to know about apostrophes is that they have two main uses: to indicate contraction, and to indicate possession. That sounds pretty abstract and not at all memorable, so here are some examples.

My writing time is being swallowed up at the moment by Baby Smith and my impending return to work, but here's a silly flash fiction I jotted down whilst the offspring was napping one day. It's not related to anything else I'm working on – just a bit of throwaway fun. Enjoy.

Still being short on time to catch up with my reading, I thought it would be a good idea to dedicate a few Recommended Reads posts to different spec-fic authors whose work I enjoy. After all, recommendation doesn't have to be about books that are new (or new to me); introducing new readers to an old favourite is a sheer delight, whilst on their part there's the excitement of discovering an established author whose back catalogue is ready to explore. In that spirit, my first chosen author – Diana Wynne Jones – was a prolific and brilliant fantasy writer who sadly died in 2011, leaving behind her so many wonderful books that it's hard to know where to start.

Wynne Jones wrote mainly for children, who she claimed didn't need things spelling out for them nearly as much as adults do. That probably explains why her books are so re-readable. If some children's literature is like a frozen puddle, shiny yet superficial, then Wynne Jones's books are icebergs: full, rich and deep. I grew up with them, and I continued to buy and read new ones as they were written – into my adulthood, and right up until she died. Not many authors have gained my whole-hearted loyalty in that way, and I think that speaks volumes for her ability as a writer to surprise and delight children and adults alike.

Some authors are essentially one-trick ponies. They have a single key idea, which becomes a series in which every episode follows the same basic formula. Nothing wrong with that, necessarily – but what I always loved about Wynne Jones's books was that I never knew what I was going to get. She must have been brimming with thousands of ideas. Over the course of her life she wrote a series of related but standalone books (the Chrestomanci sequence), some of which had almost nothing in common except the reappearance of the titular character; a completely unconnected quartet (Dalemark); another trio linked by a different central character (Howl); and about 20 more one-off novels – all for children. She also wrote a handful of books for older readers, equally clever and equally surprising, and all imbued with both a great love and a gentle mockery of fantasy and its trappings. Oh, and in addition to all that, her Tough Guide to Fantasyland should be required reading for any fantasy writers who want to avoid the many pitfalls of cliché.

By now, I'm hoping that those of you unfamiliar with Diana Wynne Jones are already racing off to your nearest bookstore. But just in case you're not sold yet, here's a little more information about my favourite five of her works. (And let me tell you, it wasn't an easy choice.)

1. Howl's Moving Castle. My childhood favourite. This may partly be because I was a little bit in love with Howl (which, according to a Wynne Jones interview I saw once, is fairly common; for a self-obsessed, dishonest, responsibility-shy coward, Howl seems to be remarkably appealing to girls of a certain age). The protagonist of the story is Sophie Hatter, the eldest of three daughters who is convinced she'll never have any adventures (since everyone knows that if three siblings seek their fortune, it's the youngest who'll succeed). She's resigned to working in her family's shop her whole life, until she is turned into an old lady by the Witch of the Waste and makes her way to the moving castle of the notorious Wizard Howl. Even as an adult, I find this book a delight: its playing with tropes, its presentation of our own familiar world as a strange place from which strange magics can emerge, the moving castle itself … oh, OK, and I'm still a little bit in love with Howl. (Incidentally, the Miyazaki film based on the book is also a favourite of mine, although it's a completely different beast from the book.)

2. Fire and Hemlock. My adult favourite (though technically another children's book). I find it hard to put into words how much I adore this novel. I first read it as a child, and didn't really understand everything that was going on, but I was left with the lingering impression that there was more to understand. Books like that can go one of two ways: one, and sadly more frequently, they don't stand up to repeated reading, and the meaning you once sensed in them turns out to be nothing more than hand-wavy vagueness on the part of the author; or two, they grow as you grow, gradually revealing the layers you always knew were there but didn't have the understanding for. Fire and Hemlock is very much in the second, more unusual category. I've read it many times; each time, I figure out something I didn't twig before, and each time, I become a little more in awe of the sparky intelligence that put it all together. The book is essentially a reworking of the Scottish ballad Tam Lin, but it's also about books and love and the power of imagination and – well, just read it.

3. Dark Lord of Derkholm. Oh, how I wavered between this and Deep Secret, another more adult-oriented novel. Deep Secret is more of a classic fantasy in which magic users secretly live alongside ordinary people, and everyday things (in this case the rhyme 'How many miles to Babylon?') have hidden meanings. Add parallel worlds (which Wynne Jones is very keen on), great characters and an affectionate sendup of fantasy fans – among other things – and you get a little of its flavour. But in the end, I had to go with Dark Lord of Derkholm, which manages simultaneously to play with all the hoary old fantasy clichés and be a proper fantasy story in its own right. (The problem with satirical fantasy, I often find, is that it forgets to replace the tropes it's holding up for ridicule with anything, so it ends up being a series of set pieces rather than a coherent story in its own right. DLoD impressively manages to avoid that problem.) The book is set in a world to which 'tourists' from our world come expecting the Full Fantasy Experience: a magical quest peopled with stock characters, culminating in the expected battle with the Dark Lord. But all this takes a very real toll on the inhabitants of that world, and so they seek a way to end the tours for good.

4. Charmed Life. This was the first Chrestomanci novel to be written, though not the earliest in the chronology. Still, if you've never read any of the Chrestomanci books before then this is the best place to start. The premise of the books is that in a set of parallel worlds (of which one is our own, and one is similar but with magic users), most people have a double in each world. But occasionally, a person is born without any of those alternate versions in other worlds, meaning that he or she has several lives and is a powerful magic user. 'Chrestomanci' is actually the title given to the most powerful of them all, a nine-lifed enchanter whose job it is to oversee magic in the related worlds and ensure it isn't misused. I'd recommend any of the Chrestomanci novels – they're all great fun and well plotted – but Charmed Life is the perfect introduction.

5. The Dalemark Quartet. I'm cheating a bit here, but the thing about these four books – unlike any of Wynne Jones's other work – is that you really need to read them all to get the full effect. The first three are set in the same world at different times and places; the fourth links the disparate storylines together. So although you can read Cart and Cwidder or The Spellcoats or Drowned Ammet as individual works, and enjoy them, my view is that the experience is made much richer by rounding them off with The Crown of Dalemark – which is my favourite of the four, but also the one that depends most on prior knowledge of the others. So for that reason, I recommend you read them all. I'm not even going to attempt to describe what they're about. You'll just have to trust me on this :-)

So there you have it: my potted guide to Diana Wynne Jones. If you've never read her books before, do read one and let me know what you think. If you're already a fan, I'd love to know which is your favourite!

Welcome to Barren Island Books, an interview show in no way related to a popular music-based radio programme. Every Thursday, I will be exiling my latest guest to a remote island with only five books for company, selected from the categories I give them. It’s up to them to make sure they choose wisely, because they’re going to be stuck with these books for a long, long time …

My interviewee this week is Sammy H K Smith, author of In Search of Gods and Heroes (coming soon from Kristell Ink) and Anna. When she's not being banished to a desert island, Sammy can be found at www.sammyhksmith.com.

So, I am now 30.

It shouldn't mean anything. Yes, I've just entered my fourth decade, but only because I happen to belong to a ten-fingered species who therefore invented a base ten numbering system. If I was one of the twelve-fingered Ka'taan, I'd only be halfway through my third dodecade; whereas if I was one of the arachnoid Zool, my fourth octade would nearly be over by now. Like new year, in which we attach vast and profound significance to the resetting of a calendar we ourselves invented, milestone birthdays are completely arbitrary.

It shouldn't mean anything … and yet I find myself staring at my face in the mirror as if it's going to start decomposing rapidly like a scene from a horror film. Feeling a momentary twinge when I get up and instead of thinking I must have been sitting awkwardly, thinking That'll be my joints deteriorating. Most of all, as is customary in these situations, enumerating the long list of everything I haven't yet achieved in my life.

Age is just a number. But as a company announcing its annual profits or an author anxiously tracking book sales will tell you, numbers measure the difference between success and failure.

When I turned 20, the very existence of 30 was more of a legend than a reality. The fabled continent of Trois-Dix, shimmering in the mist like Atlantis, barely present at all. I had many miles to travel, and many quests to accomplish, before I would reach its shores. But now … now it turns out there was a motorway that would take me there, and I jumped straight on it. All those twisty paths and strange encounters passed me by, and all the things I'd hoped to achieve as a young adventurer were lost in the process of everyday life.

In short, arbitrary or not, reaching 30 without having achieved certain things makes me feel like I've failed. And arbitrary or not, the jump from 29 to 30 seems far, far greater than the one from 28 to 29.

I think, in part, this is down to the prevailing perception – perpetuated by a thousand movies – of what different times in a person's life are 'for'. Your twenties are when you get to be carefree, reckless, irresponsible. They're for pursuing your dreams and taking risks. Whereas your thirties are intended, according to Hollywood's Life Map, for settling down. Becoming a parent. Leaving behind the follies of your youth and accepting your status as an adult with obligations to others. As a newly made 30 year old with a job, a mortgage and a baby, I'm virtually the blueprint for that model. I have officially entered the Age of Responsibility. Which is unfortunate, given that I still feel like a 20 year old inside. I still want to achieve all the things I dreamed of. I still want to embark on something more interesting than a motorway journey. But I feel like I've missed my chance.

In reality, though, life is far more complex than society makes us feel. Life doesn't give you a cut-off point for reaching your goals, after which point it slams the door shut in your face. Life is about growing and learning and changing, redefining what's important to you and getting there when you're ready, not when a number suggests you ought to. And learning to stop being selfish isn't at all the same thing as giving up on your dreams. I may still feel like a 20 year old, but it comes with a hell of a lot more knowledge and experience than I had back then. I haven't missed my opportunity to succeed. Rather, I've gained the opportunity to do it in a different way.

So, screw 30. I'll have my adventures when the time is right – or, if I don't, I'll have different ones. (After all, even the motorway of everyday life is its own adventure.) In the meantime, I've decided that since I have ten fingers and ten toes, I will now be using a base twenty counting system. Which means I'm only halfway through my second icosade. Practically a teenager.