I healed my very first level 50 dungeon in Cleric Stance. I think the tank thought I was a little special because he pulled really small. No one bothered to tell me and I was so nervous I didn't even look. I remember thinking that it was crazy hard to heal through and I contemplated not playing healer ever again.

And then when I left the dungeon I noticed and I felt like a flipping idiot. Thankfully after a year I finally got (kind of) better... I think.