I've put a lot of thought into this the last 4 years since I first came across this thread.

I'm a stander, always have been, but when I found out that most people stand, I gave sitting a try. Rationally and empirically, I think that sitting makes more sense, yet I find myself over and over and over and over again impelled to stand. I don't mean that I autopilot into standing, mind you; I mean that as much as I tell myself that it makes more sense to sit, I'm impelled to stand. I never really could understand why this was.

I think I've finally started to understand: I can't not look at my poop after I go. I seriously just cannot bring myself to do it unless I really need to (eg: public bathroom with an automatic flusher that goes off if I move any more than 2cm). I don't mean this in some juvenile "tehe, poop is funny" sort of way, either. When I shit, I *have* to see how big it is, its consistency, its shape, color, representative chunks, etc.