Why we continue to make New Year's resolutions - and inevitably give up on them

Some people have willpower. You can see it holding them up – all can-do and sinewy, it wraps around their bones and fortifies them, like Wolverine's metal bits. They plough through projects and wrestle workloads, all too often unaware that their ability to see something through to the end puts them in a tiny upper percentile of useful human people.

They do very well at this time of year, people like that, because they give up smoking or take up paragliding. And they don't just do it for a day – they manage it. New Year's resolutions aren't for everybody, you know, so consider which camp you're in before you start beating yourself over the head with whatever flimsy pretence of health you're trying to embark upon this January.

I am not like those willpower people. The only resolve currently eddying around my system is the hangover- curing antacid of the same name.

Ever since I can remember, I have been utterly incapable of sticking to any resolution I have ever made. When I was little I once decided to tidy my room – to spring-clean it, if you like – by emptying every single cupboard and drawer on to the floor and putting everything back, only much more tidily. Halfway through, I got bored and simply pushed all the toys, clothes and books under my bed and hoped that my mum wouldn't notice. She did.

My whole existence is still, in many ways, like that bedroom. My life is littered with the rusting hulks of fads co-opted and then forgotten about, the bare bones of things I couldn't be bothered to finish. I push them under the metaphorical bed and cover them with snazzy throws, but nothing hides the fact that I am a relentless self-improver of the very worst kind: the kind that never really improves herself at all.

I make lists that always start with the same instruction: "Do more exercise." I make these lists about once every three months, then fail to implement anything on them. Once, to my eternal shame, I wrote one of these lists in a notebook that, when I leafed through the previous pages, just contained list after list of things I had never got around to doing. A phalanx of failed frontispieces, a life unameliorated, more exercise not done.

After eight months of intensive physio on my broken leg this year, my therapist told me in August that our work was finally finished. "Am I all back to normal?" I asked, excited. "Could I run a marathon if I wanted?"

"Well, Harriet, given that you couldn't be bothered to do most of the exercises I gave you, I hardly think you'll be training for a marathon any time soon, will you?" She looked long-suffering at me and my ilk. But she had a point. Yet still, in my head, there is every chance that I might run a marathon one day.

Sometimes I manage things for a little while. I started swimming again properly this year and kept it up for quite a decent amount of time, although it is now a few months since I last went (obviously). Sometimes I know even as I write them down that my resolutions will never come to fruition. Such as the "Eat more vegetables" exhortation – I'm inwardly snorting and shaking my head by k the time I form the curlicue on the "g". But somehow, the act of writing these things down calms me; it solidifies them in the shape that I want them to be – the fact that this bears no relation to the reality of the situation or to me is immaterial. Writing things down is an act; making lists lets things be.

With these, I am cataloguing chaos all comfortably within my control, whereas in real life, the moment in which I choose chocolate over vegetables (every time) rests solely in the hands of the gods. And the gods appear to prefer a Boost to a banana. (Once I tried to make things easier on myself by making the vegetable rule more specific and less nebulous: "I will eat only bananas before 4pm." I haven't touched one since.)

I know this makes me sound like a character from a Beckett play. But on the surface I'm a fully functioning, responsible adult with organisational prowess and practical capabilities well above those my habits might imply. I meet deadlines (just about), my flat is tidy and my hair is brushed, most of the time. My lack of willpower isn't even born of any real sense of dissatisfaction with my lot, and it doesn't prevent me from doing the important stuff, such as paying my rent, keeping my job, living a full and well-rounded, if not exactly healthy, existence. It's more a sense that I could be doing all of these things as some other, slightly better incarnation of myself.

That's why I've tried, in the past year, hair dye, fake tan, hair extensions, eyelash extensions, dance aerobics, hula-hooping, a personal trainer and Vaser lipo. But it isn't all bodily vanity – oh no! I've also had a go at embroidery, learning Spanish and I nearly joined a choir, which I almost certainly wouldn't have gone to after the initial dreadful session. I alphabetised my books once, and tried to keep important paperwork safe. For a time, my flatmate and I used our grill as a filing cabinet.

I kitted myself out for winter with all the wet-weather cycling gear I'd need, then rode to work once. I promised myself I'd go to loads more talks and debates and general cultural events, and then went to one. I told myself I'd read 50 books this year, by writers such as Nabokov and Philip Roth, and I started listing the ones I got though. The list reads The Fifth Queen by Ford Madox Ford; Game of Thrones books one to five.

It's a modern sickness that afflicts far more people than most of us realise. Certainly, if you're one of the capable can-do sorts, you won't have even begun to imagine that so many of your species devote so much time to trying and failing to be anything other than who they are.

It's more of a female tendency, but that isn't to say men are immune – the fact that Men's Health sells so well is proof of that. There's an ever-growing vein of self-improvement literature that has supposedly generated £60m for publishers in the past five years; in the US, the total market (including videos, seminars and so on) is said to be worth $11bn. Helping us realise our dreams of validation and vigour is lucrative – even more so should the poor saps then fail in their mission and find themselves in the market for another cure-all.

Self-improvement is as much of an addiction as yo-yo dieting, or smoking, because the whole deal is founded on the notion that you are most likely not the type of person who will ever be satisfied with who you are, or what you have. That's not to say it's a bad thing – those who constantly strive to improve may well be a bit dull, but we're not immoral.

It shows you have get-up-and-go. Or something. But there's only so much get-up-and-go one person can have; at some point it turns into sit-down-and-stop. That's why so many of the things offered around this time of year, to help strengthen our resolve and keep us on the straight and narrow, have such a punitive angle.

I once went on a week-long yoga detox, which involved absolutely no food (whizzed-up vegetable drinks only) and two enemas a day. Halfway through, the intense longing for a pork pie actually made me weep but, seeing as there was no way to fall off the wagon (the Goan setting was so rural that there was hardly even a wagon, in fact), I had to stick to the regime. It was miserable, so as soon as the plane landed, I went to McDonald's. I have never felt more guilty or contemptuous of my lack of stamina. But by God, it was a great burger.

So I do understand the people who go on bikini bootcamps or do British Military Fitness in the park on Saturdays. I wouldn't want to be one of them, but I get it. As with so many things in life, unpleasant tasks are much easier to get on with if someone is shouting at you that you have to do them, or they have locked you in an ashram with no food.

Perhaps the main problem with self-improvement among my generation of giver-uppers is the lack of self-motivation. In other words, we have it too good and always have had. We rarely do things we don't like doing; I've never had to pull myself up by my bootstraps. Is it manifesting itself now as insolvable existential guilt, this Sisyphean striving for an eternally elusive end result?

No, far more likely an answer is just that I'm self-obsessed: apart from reading, watching telly and drinking, my main hobby is me.

And I'm not alone. I know I'm not, because I haven't spent £60m on self-help books all by myself. And because every so often I see people on the Tube reading How to Get Rich Quick and making notes, or How to Date Someone Really Fit and then checking their reflection in the carriage window. Not everyone is a millionaire or going out with a model, so other people must fail too.

We're simply not used to things that aren't a quick fix. Hate housework? Get a cleaner. Can't be bothered to read a book? Wikipedia. There are very few chores, per se, that actually exist any more – just imagine what medieval peasants would think if they saw us on our bikini bootcamps. They'd be completely befuddled. They'd think we were the village idiots, not them.

But that's how it stands. We invent chores for ourselves, we make ourselves jump hurdles – and some of us manage, some of us don't. We opt for things that we think will make us better people. Then we realise it takes quite a lot of effort to be a better person. We fail, we chastise ourselves, we loathe ourselves, we try again. It's a Hegelian battle of wills between what you want and what you think you should want.

I've tried being a self-starter. At university, during the hellish revision term before my finals, I decided to embark on a running career to further improve my mens sana. I got all trogged up in the kit then went out for my run at precisely the time the pubs in the middle of town were emptying. I ran about 200 yards, terrified that somebody cool might see me in my PE kit, then I turned around and went back to watching telly. In my PE kit.

That incident of humiliating failure I don't count as strictly my fault. The intention was at least there. Ditto with the embroidery – I bought a "how to" guide and everything, but then I was too busy doing other stuff to try it. I even booked and paid for the dance aerobics – the problem was that I went out the night before the class, had loads more fun than I was expecting to and took the executive decision not to go the next day.

And actually, I am happier for that decision. I am happier doing things other than embroidery – not to knock it, but I don't see the point in doing things that one isn't passionate about. I am passionate about seeing the people I love and laughing with them, and that's what I spend most of my time doing.

So this year my resolution was simply to do things that would make my life better, and I'm not convinced that learning a new craft or taking dance lessons would. I try to improve myself periodically but I never expect anything from it. It's a diversion, a stab in the dark at finding a hobby.

In fact, perennial self-improvement is a hobby in itself. And it takes up an awful lot of time, you know.

Doomed to failure: Harriet's personal history of fizzled enterprises

Tidying my room

Got bored, pushed toys and clothes under the bed

Running a marathon

Got as far as asking my physiotherapist whether it might be possible

Eating more Fruit

The chocolate looked more inviting

Cycling in Winter

Bought all the gear. Did it once

Detoxing

Made it through week in an ashram; once off plane, skedaddled to McDonald's

Running

Made it 200 yards down the road, returned to TV