Be careful not to complain when answering this question. You should also make sure not to cast a negative light on any colleagues. Your answer should focus on something relevant, and you should also assure the interview panel that the pet peeves you mention don't ever affect the quality of your work.

"I don't have many pet peeves, but I will admit that people arriving late for meetings or appointments is at the top of the list. I respect everyone's time and feel that should be reciprocated. That being said, I understand that people sometimes run into unexpected delays, so I do try to be understanding. This is especially the case for patients, and I never let someone arriving late for an appointment affect the quality of care I give."