This is actually a great part of why I loved tanking lower content as a warrior. Even if the healer was a jerk, I was able to solo most of the mobs pretty okay on my own, so it's not like we absolutely required them. Being in a strong position like healer/tank gives you a lot more power over the group, which is a huge plus if you're a nice guy . I'm reminded of this time actually when I was going through Qarn, the Dragoon was absolutely atrocious to play with, and I felt terrible for the other two players. But I continued to go through it for the other players' sake, and encouraged them to report the person. In another instance, I had another person start berating the team, so I threatened to leave if he didn't act respectful. It shut him right up. Obviously, these tricks don't work every time, and for those in the dps role, there's... not a whole lot you can do, sadly. The most you can do is report the person and then choose whether you wanna deal with it, or just leave and deal with the 30+ minute que timer.