Well, I stayed off MN all weekend and managed to achieve a thing or two.
I experimented with location - I took all the Christmas bedclothes (no, I don't have special ones but we did have quite a lot of guests) to the launderette, along with some cards I had been going to send as Christmas cards, and wrote something like 10 of them (with proper notes in them, not just 'Dear xx, HNY from the LW family') in between washing. 
Now all but the three whose addresses I knew by heart are sitting on the dining room table waiting for me to dredge up the relevant printout. 
I'm another of these 'clever' ones. Always got top marks for attainment and crap marks for effort. My educational achievement curve has been pointing inexorably downwards since O-levels. (University was a challenge, as they had cleverer people there!
)
I'm not trying to cause a schism here but I think we have two main kinds of people on this thread - the procrastinator/underachievers, who may not have got round to working out what they want to do with their lives yet, and the procrastinator/self-loathers, who might be in jobs they quite like and are good at, but where they are convinced everyone else thinks they are a waste of space.
Going back to the self-sabotage that someone mentioned, I've always done it - leave work to the last minute so it has to be a rush job; stay up late and get drunk the night before a job interview rather than be refreshed and clear-headed. In my more arrogant (and tongue-in-cheek) moments I've told myself that I do it so as to spare the world the full dazzling force of my brilliance, though fear of failure ('It doesn't matter if it was crap as I wasn't really trying anyway') is an interesting theory I've not previously considered.
Halfcaff if you do drink it I'll know you hate me 