In a social studies classroom, the substitute was drawing a map of Pittsburgh on the board for no reason:
Substitute: And here is the football stadium...
Class: what does this have to do with...?
Substitute (ignoring them): And here there is a big lift that leads way up high to these mountains where there are giant mushrooms and-
Boy: what if you're mitophobic?
Substitute: What's that, afraid of heights?
Boy: No, afraid of mushrooms.
Substitute: Stay on topic.