I'm looking at the the thread here
As I say in the comments, I wonder if a game that does not end/have a final win condition actually exacerbates obsessive compulsive dissorders in people?
It either goes one way - you don't care, because you can't finish it anyway. Or it goes the other way - because there is no end to get excited about, and because you must get excited about something (rather than "don't care"), even a second faster in progression somehow becomes all consuming important. Much like some people have an overwhelming urge to touch every fence post as they walk, or align all their mug handles in one direction, or they become horders (oh wait, that's a bit too close a parralel with a mmorpg, isn't it? Not even an analogy anymore...)