Fool Me Twice…

(Our class is introduced to an algebra teacher at the new school.)

Teacher: “Unlike most teachers, I’m not asking you to write down everything I say. But if I repeat something, make sure to write it down for your own good.”

(A few minutes later he makes a trivial mistake in a formula.)

Teacher: “I’m a fool! I’m a fool!! *a few seconds of silence* “Write this down: [Teacher] is a fool.”