Had an ignoramus of a tank trying to dictate how to play to others in Labyrinth just yesterday (in between liberal volleys of insults, accusing everyone else of being WoW noobs, harassing another tank for having a macro to announce taunt, and demanding to be thanked because he was "clearly carrying the raid" - while losing threat on the bone dragon, being relegated to Platinal duty, and then stacking all of them in a pile next to the central platform). "Advice" from someone like that is clearly to be ignored.

Mercifully, most people are better about it.