I have another one "Please bring lose change to buy snacks" Big cringe. My biggest pet peeve is backchat. If a student is going to be rude to me for the sake of being rude to me, I have no patience for that. Especially since I make such a conscious effort to be respectful to them, even when I'm giving them consequences. And I agree with the lying. I really dislike this trait, in my professional and personal life.