Do not do something stupid knowing it's my job to keep you in check and then mouth about how I called you out on your stupid behavior. Seriously.
And learn to conduct yourself in public. Fifteen or not, now is the time to learn how to be around other people without being a general annoyance.
Oh, and diplomacy, a skill you won't have to employ for another 5 years (because we apparently don't require high school students to act with any), means you can sit in a room with someone you don't like without causing problems. I've managed to do it and it hasn't even affected your grade.