I love the post especially Dori at the end. I can't tell what I am and but I have only done one baby ultra (50k). I had a great 21mile run yesterday. I didn't start wondering why until I got home and was relaxing on the couch. I'm pretty sure I run because I enjoy it at the time and because I like staying strong and fit.
Didn't know that Masochist and Hedonist were mutually exclusive
Whilst I've yet to run an ultra (I've "only" run a marathon), I'd have to say that there has to be a bit of masochism and/or self-loathing involved in running long distances. You've pegged that in the post run internal dialogue you wrote about (quite brilliantly, I might add).