I received an email three weeks back from a discipline priest who told me she thought her performance on the healing meters was too low. Though there wasn't any pressure on her from her guild to change what she was doing, she was bothered that her peers often outhealed her by a significant amount -- even another discipline priest with worse gear and a laggy computer. She told me she'd first noticed it at the start of Cataclysm, despite the fact that her performance on meters should have gone up with the change to combat logs (which allowed absorption from Power Word: Shield and Divine Aegis to register on meters). She kept up with her assignments regardless, and none of her targets ever died, but something just didn't seem right to her.
The priest linked me her armory but said that she didn't think it was anything to do with her gear choices, which I agreed with upon my own inspection. She also described what she was casting, none of which seemed horribly egregious to me. What could be wrong?