I could try to be all clever about this and link it up to preciousness of words etcetera, but instead I'm going to be shallow and link it to appearance. Do you comb your hair and paint your nails (regardless of gender; who wouldn't like a little nail varnish on their bits?) before sitting down at the keyboard?
If you're anything like me, your hair will be barely brushed; your clothes will be covered with yesterday's dinner; and your face will remain unwashed until noon. Gosh, I've painted a very attractive picture of myself, haven't I? It seems the more primitive I feel, the better I can connect with my characters. When I'm all scrubbed up and dressed for the outside world, I just can't concentrate as well.
So tell me: vanity or grunge?