I knew a college chem prog once. His final exam had a bonus question: 5 points for every member of the lab janitorial staff you could name. He told me about one student who objected to this question, how was he supposed to know their names. He asked if the student had ever worked in the lab after hours, yes; was janitorial there, yes; did you bother to talk to them, no; do you realize how much more pleasant it is to work in the lab because of them, silence.
I love it!