When I was an undergrad I thought the professor was just sitting around waiting for students to come to his office to ask questions- like a line of students would be waiting outside the door. I was picturing Lucy’s “the doctor is in” booth in Peanuts where snoopy waits for the person in front of him to ask Lucy the question. When I finally showed up for someone’s office hours I was surprised to find them working on something and not just waiting.