Jeez, Rick, I read your message and it reminded me of just about everything I ever got pissed at in a session. And it all comes down to rudeness. Moving in on people until they can't play (happened to me last friday) stealing your chair or asking you to move because they happen to like the spot you're in, talking loudly when someone's trying to play, hogging the session by either not ever stopping or by playing louder than everyone else. Strangely enough, I've never encountered anywhere I've ever played. Now I need to calm down!