I was recently helping a buddy of mine with an 8 man dungeon because the Tank was being bossy and kicked him. But I usually notice when I DPS the Tanks do act a bit strict? I was also kicked for not listening to Tank!
As a Tank myself I always pull between 6-15 mobs at once to speed things up, while being cheerful and laid back to keep things fun. I also take advice and listen to explanations from DPS.
But sometimes people think I'm here to boss them around!?