I really wish mmos would have dungeoneering tutorials where every role and their relation to aggro/emnity would be explained. I feel it's ultimately the game's responsibility to educate players on these matters, not us players. As a tank player I've grown a thicker skin over the years but really, some people are just atrocious in their behavior towards tanks and healers. And even though dpsers are lovely expendable due to the infinite supply, there's no way to get rid of them from a group mid-instance in this game (is there?).