Dude it's so annoying when that happens.

I had a run in Dun Scaith the other day, running as SCH, in which the other healer was SCH too. The dude was playing as if I was a solo-healing WHM, and didn't even have Eos out (this is actually better in the first two bosses but vs Scathach and Diabolos Eos is much better than Selene imo). The point is... the other SCH was doing nothing except DPSing, and our tank kept MTing every boss. That wasn't really a problem until we reached Scathach. Of course, being Dun Scaith, everyone was taking avoidable damage and it came to a point in which I had to stop DPSing completely because everyone was either dead or taking damage by the thousands, the tank was eating shit, and the other healer was dead too.

I raised the other SCH to help me with raises (this was after everyone died AFTER I had already used the healer LB :'), and he kept DPSing to his heart content, so wtv, I kept solo healing.

At the start of the Diabolos fight, our tank has the audacity to ask other tanks to MT because "he was MT and both healers were DPSing."

Like, excuse me? Even if the other healer had been helping out, heck yeah I'm gonna DPS even if you're the main tank. Him whining about it, though, that was just adding insult to injury, since I had so very little DPS windows because everyone (including the tank) kept tanking avoidable damage with the face. I left the instance before he pulled Diabolos and left the other SCH to solo heal. A friend of mine was in the party, and predictably they wiped really fast cause I wasn't there to babysit them.

I felt bad about ditching my friend with a bad party, though :')