Mine too, tongue in cheek that is, but my humour often goes over the heads of others.
You are a teacher, you know how to assert your authority, it takes much skill. My headmaster inadvertently taught me a very useful lesson. He would have some miscreant standing in front of him, the headmaster wouldn't say a word. The miscreant would try to blag with a load of baloney. That's when the headmaster would allow his glasses to slide halfway down his nose and then napalm the miscreant with a stare that could melt a polar ice cap.
My working life has been in the distribution industry. The head honcho of some fifteen hundred or so potential miscreants. It was a very satisfying moment when I overheard someone say: "I !&$%ing hate it when he stares at me like that, over the top of his glasses!"