Meh. In 5th grade we had a substitute, who was reading us a story in the library. It was about a mule, and she asked whether anyone knew what a mule was. I raised my hand and said it was the sterile offspring of a horse and a donkey.

Got sent to the principal's office, because she insisted that no, mule was just another word for donkey. Even after I showed her the dictionary entry (we were in the *library*, after all).