I've got some minor pet peeves but I have two "BIG" ones. You can tell me to be quiet, hush up, etc., but if you tell me to "shut up", I'll just about fight you. Those two words used together are just about the rudest thing you could say to me. I'll end a conversation, an evening and have ended a friendship over the use of that phrase.
My other monster sized pet peeve is when someone plans my time without consulting me. You may do it once, but you won't do it twice to me. The only time you are allowed to make plans for me is if you are paying my salary.