@Innue: They probably have, but I wouldn't say that's the problem. To me, the interplay between characters is always there, even if it's a "plot moment". But I always find it really dull. Even when it isn't just generic friendship stuff, it doesn't really capture my attention, and I just wait my turn if it ever comes.
As for what has inspired me, there's no real pattern. I've read plenty of stuff that's supposed to be emotional, but only once did I read something that actually made me feel for the character. And when I think back on it, I really can't say for sure why it was that one post stood out to me.
@Genkai: Like, if an RP reaches the point where there's a week or more between posts, IC or OoC, I start to think it's going to die. And usually it does. I don't necessarily leave entirely, but I've never made a larger effort than necessary for an RP that reaches that point. In retrospect, that probably doesn't help matters, but if it takes weeks to get anything done like you said, I'm not in a mind to make a personal effort for the sake of an RP with a low chance of survival. I'm just not that kind of benevolent superman roleplayer.
And yeah, I would take up the role of GM, but this usually occurs when I'm a player in a big RP. Can't really just take over when I feel like moving things along, can I? I have started my own RPs before, but they failed due to the usual reasons (players left, activity waned). Like I said before, I'm not such a great person that I can run around inspiring activity and getting things going, and I would probably just fail again as a GM.