PVP is by far the biggest complaint group. They complain about each other and the game almost constantly. Pretty much all boils down to who sucks, I am better then him/her, game is unbalanced(if I am not the OP one), and blizzard only cares about raiding QQ almost constantly. But when you look at almost every change made in the game it is usually to balance PVP and ends up screwing over just about everyone else even though those others make up a much larger portion of the community.