Deadline met.

Ah, I feel so much better now!

I think it's all about the deadlines, and the reason blog writing flows so easily is that I've come to feel that once you start a post, you've essentially already taken on the deadline. Opening a new "compose" window represents a commitment to hit publish quite soon. It is a mellow, fuzzy deadline, so I feel especially good about it, but it works like a deadline just the same.