Dream the living ... the real returns probably won't pay for your train fare. Photograph: Lewis Whyld. Photograph: Lewis Whyld

What people really want... is to be broke. At least, that's one likely interpretation of a new YouGov poll that shows more people in this country would rather be a writer than anything else. Now it's possible they've all got their eyes on the JK Rowling squillions, but the financial reality is rather more depressing. Most book manuscripts end up unwanted and unread on publishers' and agents' slush piles, and the majority of those that do make it into print sell fewer than 1,000 copies. So while there are a small number of writers making a decent living, something like 80% of published authors earn less than £10,000 per year.

It's not even as if writing is that glamorous. You sit alone for hours on end honing your deathless prose, go days without really talking to anyone and, if you're very lucky, within a year or so you will have a manuscript that almost no one will want to read. Your friends and family will come to dread requests for constructive feedback - which they know really means just saying, "This is far better than Amis or McEwan" - and if, by some small chance, you do land a book deal you will spend the week of publication wondering why your book isn't piled up at the front of Waterstones and why you haven't even picked up a single, measly review in the local paper.

None of this would matter much if being a writer was to somehow make you fantastically attractive. After all, who would care about being broke and angst-ridden if there was the compensation of hordes of groupies? But it doesn't. At least, not in my experience. Or that of any other writer I know. Though it may well be different for those whose books sell in the hundreds of thousands. Even if, by some small chance, people do think you are modestly talented and creative, they still aren't going to fancy you any more.

But this urge to be creative - or more importantly, perhaps, to be seen to be creative - surely must what makes writing so irresistible to so many. Few jobs allow a purer expression of the self. You can create your own worlds, your own characters and your own stories; the only limit is your own imagination and talent. And this is where, you can't help feeling, the whole thing begins to fall apart. Because for most people there is a huge mismatch in their perception of their imagination and talent. For when people talk about wanting to be a writer, they don't usually mean they just want to write something in their own time for their pleasure. They want to do it for ours' too.

One of the pleasures - and nightmares - of writing is that most of us can do it. Anyone with basic literacy skills can get a meaningful sentence down on a page. And, taken on its own, any one person's sentence may look not much different than one knocked out by Margaret Forster, so you can begin to see why people start thinking of writing as their creative way out. It's only when you've got several paragraphs of sustained writing that you begin to see the difference.

But then... All sorts of rubbish gets published anyway. Jeffrey Archer can barely string a sentence together that most other writers would have the nerve to submit as a first draft and he's one of the most successful authors around. So there is no magic formula. There is no clear dividing line between good and bad, between the publishable and the unpublishable.

Out of this has come a small industry in creative writing courses - frequently run by writers who can't make a living out of writing - to trade on this grey area. For every writer who signs up for a course and lands a deal there are several hundred more that remain deservedly obsucre.

For while a creative writing course might teach you a little about structure, characterisation and dialogue, it won't teach you a thing about creativity. As a reader, I reckon I can almost always tell which writers have come through a creative writing course. Because they are the ones whose work is dry, lifeless and formulaic. Whatever creative flair was present in the raw first draft has been carefully edited out by the time it's published. And the only thing you really want to do by the time you get to the end of the first chapter is sleep.

So, by all means, write, if you enjoy it. But, if you value your sanity - and that of any readers - keep it to yourself. Keep the dream; just don't give up the day job.