This happened to a guy I know.

The teacher wanted to divide the PE class into two teams so he had them form a line and number off "one, two, one, two, . . . etc." My friend was standing at the right hand end of the line and thus was supposed to be the first to call out "one"—but he was gathering wool and stood there mute. Enraged, the teacher stuck his face three inches away from our hero and roared, "ARE YOU ONE? ARE YOU ONE?"

The reply: "Yes, sir. How did you know? Are you one too?"