"Horror Stories" you say?
I'm a lvl32 WHM who wants to run Brayflox for EXP.
Some Dragoon wanted to finish ASAP and kept pulling mob after mob, completely ignoring my MP (and the simple fact that he's NOT a tank).
The tank, instead of being angry at the DPS, got angry at me for "not keeping up".
Problem is, it's not my job to heal reckless DPS.
Another problem is, the tank couldn't even "keep up" with it himself because due to massive heal output I was constantly drawing adds. OR he simply ignored them. You decide.
Both were lvl50 players scaled down, mind you.
So after they complained about me being too slow and them being in a hurry, I told them to lean back and chill while they wait for another healer, just before I left them.
Dealing with terrible players is NOT my job.
I can just leave and find a new, proper party in less than a minute.
There is no reason for me to tolerate their behavior.
So what makes these people think they can get away with it?
Because they don't. Not on my watch.