... Because they were fire-chained to me in that one dungeon where you have to run away from your linked party member to avoid death.
... He didn't help me break the fire-chain so we both died... and then when we respawned, he said, "Are you using DPS spells?" To which I said "Yes" and He replied "Well then don't. Don't use anything but heal."
I have always kept my party members up at 90% health or higher, used my DPS spells on adds and boss, and never struggled with my mana. I rarely have to revive anyone unless, like in that scenario, they ignored a boss mechanic.
I think I am a pretty good healer, as it is such a simple class and you can do no wrong if you've played MMOs for a long time. But hearing him blame me made me feel so defeated