This whole, "treat your tanks better" thing works both ways. I have seen some really rude and idiotic tanks in my time as healer & DPS.
I have also seen some very rude and idiotic healers/DPS.

For the tanks out there, not every run needs to be a speed run if you don't have the aoe for it. Please recognize that. And DPS, not every run should be lazy or easy going if you have the AOE for it.
Knowing this, 90% of the bad attitudes I get from tanks or DPS starts because of a speed run gone wrong. Tempers flare because one side doesn't want to speed run and the other does or what have you. The other 10% of arguments I've seen is people tossing out "advice" the other player doesnt want or need and so again, tempers flare up and an altercation ensues.