Depends where you are when they ask - inside the sterile area or in the non-sterile side of the terminal and you plan on flying, I would avoid profanity and just tell them it's not their concern or to reference the boarding pass in their hand.

If you're in the non-sterile side and not flying or out of the terminal building (i.e. parking lot, roadway, etc), let your conscious be your guide - there is absolutely nothing they can do to you.