Not a TSA agent, but a UK immigration agent when entering the UK with my dad.

"How are you two related?"
"Father/son"
"I thought so, but wanted to make sure. The other day I had a man about your age (pointing at my dad) with a girl about your age (pointing at me) and I said 'Is this your daughter' and he said 'No, that's my wife!'"

Wish more TSA and other agents could have a sense of humor, it livens up the monotony of travel, especially after 8 hours on a flight.