Kicked for being Dps death knight in wotlk when doing dungeons. But My favorite was back in wotlk when you had to link achievements to join raids, by using a addon that faked achievements in chat I joined a group for a new boss in voa. After we killed the boss and I got the real achievement and a piece of gear, I was kicked and harassed by a crazy guy who did not get the loot and he was pissed of that I could join without having the achievement.