Resolutionary thinking

By the time many of us woke up this morning, we had already broken our new year's resolutions. Research by the University of Scranton in the US shows a quarter will have been abandoned by January 7 and ultimately 92 per cent are doomed to fail. And, deep down, we know these grim statistics when we make our resolutions, all of which raises a curious question: why do we bother?
Part of it is that even a temporarily honoured resolution is better than none at all, and there's also the prospect of beginning the new year on a positive note. Yes, I will lose that extra weight I gained this year. Yes, I will put more effort into keeping in touch with friends and family. Yes, I will save more of my income.
Different people take different approaches: do you set a vastly ambitious goal or do you set small, achievable ones? Do you choose fuzzy targets ("Get organised") or strictly-described and empirically verifiable ones ("Lose 1kg per month through 2014")?
At least there is another statistic from the University of Scranton to make us all feel a little better: explicitly stating a new year's resolution makes it 10 times as likely to happen as making no resolution at all.