My worst habit is probably getting all fired up about making something, and then making it, and then getting bored with it. Some things don't get sewn up for aaaages. I guess I'm a process knitter, not a product knitter.
Unfortunately it's the same in my career too - I'm an ideas/concept person, but I forget all the little tiny details. I don't mean to be sloppy - in fact I'm a perfectionist - but it's just how I am - mind always racing away onto the next thing. My boss and I have recently fallen out over this to such an extent that I am seriously considering my future career options. Time will tell.
I think I take after my dad, bless his soul, in this respect. He nearly always had his flies undone and would regularly miss belt loops on his trousers; he'd also tuck his shirt into his underpants so that they showed over his trouser tops. A fashionable look now, but not back then! :)