Indecisiveness. It annoys me when people are really indecisive and have trouble making up their minds on seemingly simple things, yet I've been guilty of the same.
When people show frustration. I feel put on the spot here, like I'm supposed to help and suddenly make everything okay, yet I've done the same to others.
Back in my teaching days, I hated it when students approached me and tried to challenge the grade I gave them. Yet, there were several times as a student when I relentlessly challenged a grade I received if I truly thought I earned better.