> One pet peeve is people who ask "can I ask you a question?"

Back when I was TA'ing a course in college, about half of the students on average in office hours would start their conversations with me by saying "I just have one small question." I'm not sure what was worse, when they didn't just have one question (or it wasn't small) or when the question was so small they could have gotten an answer by the time they finished assuring me that they weren't going to take up much of my time.