Twitterpated

It's 2am and I'm thinking the worst. For every topic of ongoing situation in my life, I can't stop imagining and anticipating the worst case scenario.
Why does this always happen in these late-night hours? The first possibility is that when everything is quiet the fears that you've been too busy to nurture begin to manifest themselves. Or sometimes i feel that life is so unexpected that if I get as far as imagining something, it won't come to pass. Maybe by the end of the day I'm just crabby, because somehow optimism is something that becomes spent through the course of the day whereas pessimism comes in a steadfast supply. Otherwise, is it really that this is somehow the time of day when I like myself the least? Makeup-less, tired, and in nobody's company?
I always feel better in the morning.