Me and a friend rolling double druids (I'm going balance/resto he's going feral, we can both DPS or he can tank and I can heal, whatever's needed). So we're doing RFC, which I should point out that me and him lacked any sort of instant (like how warriors get sunder) or AoE with a respectable amount of threat (like how warriors get TC) before 16, where druids get swipe. So AoE pulls are pain. To compensate, we figure the warrior (who's lowest level, no shield, half the stats of my friend) would tank one mob, my friend would tank another, and we'd put the warlock pet on a 3rd (the max number per pull in RFC is 4, but 1 non-elite).
The warrior would just attack the mob my friend was tanking, saying "I'm not tank, I'm DPS!" So I'd end up healing myself while everyone's trying to do everything else...we didnt wipe, but it still was a pain in the backside.
Oh yeah, he would also charge in while I'm drinking because he had rage left over and "I dont wanna waste rage, if I dont have rage I cant use my skills." He was promptly kicked at that point (we'd put up with him til then).