Just wanna add up, Im new but not real new to the genre
happen to me most of the time on dungeon, when im getting a ton of damage without seeing any incoming heal, then i see some stone spell on the mobs XD, sometimes healers do neglect their job, cant do anything since they are locked with the animation, but i appreciate if they assess the situation first before doing some dps, if you think the tank pull too much then forget dpsing for a while, because they need you full time at healing, if you think the tank can take a punch with minimal healing then dps at will.
if i die its fine, im doing my job, keeping my CD at a good rotation, pull mob depends on the capacity of mydps, make sure aggro is on me ALWAYS, the rest is up to the healer, we can keep doing the dungeon all night until such time everyone understand their role and purpose.
real story: we got 3 wipe straight, then the healer said "OK, ill going full heal, LOL" we finish the game EZ
lesson: just keep in mind your role to the team, party first before self satisfaction.