My only problem with Season 2 (and it's a big one, unfortunately) was the development of Pierce's character from being a clueless fool, into some sort of manical ass, bent on destroying everyone in the group.. The arc grew VERY tiresome for me, to the point that even the best episodes lacked. It would have been fine had it lasted only a couple of episodes before resolution, but I think they overplayed it..
I was in the same boat as you, however, Pierce's monologue about pushing people away, testing them, made his ass behavior understandable, and actually makes him a whole character, someone a little more complex, which interests me.
Now, if they don't redeem him, then I'm gonna be annoyed.