When one thinks he/she is the smartest person in the room and feels they have to explain everything that comes out of their mouth to the "dumb" ones.
Nigel: We should call our dog Pavlov.
Nigel: You know cause every time the phone rings he thinks it's time to eat.
Tammy: Did you really have to use "teachertalk" with me?
Nigel: Thought you didn't know.
Tammy *frustrated after being done this way day after day*: I'll ask you if I don't know something. Please don't proceed to explain everything to me. I'm not stupid.