What's the best/funniest/fav comeback?

My uncle called me one day and asked what I was doing I said I was driving past one of the local high schools. he said what are you doing looking for a new girlfriend. I said hey I may start dating them when they graduate but at least I don't get mine from the elementary school. He had no response because he met his wife at his daughters elementary School because she was his daughter's teacher.

The truth

"Your Mum wears my old army boots"

Just laugh out loud and say "oh my lord" and then refuse to comment further.