That's every MMO is that ouy're almost entirely dependent on who you play with, and they easily make or break the game. It's happened with Team Fortress 2, the only reason I play on CC2 is cool is because I don't hear those fucking BONK songs or get yelled at by people who think the game is a concentration camp or a stereotypical army base. If I wanted to be yelled at, then maybe I'd join the army and even they won't tell me to "Rip off your cock and shove it up your ass".
Regarding what Tycho said about people bitching about the healers, I got that a lot from having played healers that weren't specced to just self-heal in Guild Wars, TF2 and others.
In the past hour of trying to find a good server of TF2, I received quite a bit of bitching from people who've likely never even played a medic since release. I'm trying to heal you, Demomen and soldiers. When you're at Red Health, you DON'T blow yourselves out of range of the medgun and then bitch at me because I can't keep up.
Scouts, when I invuln you and w'ere at a control point, that means STAY THERE. It does NOT mean to run OFF the control point and Leeroy. And if you get killed because I decide to invuln the heavy that's trying to capture the control-point instead, not the leeroy.