The word "underpants" bothers me so much that I would be hard pressed to hide the shudder and gag reflex I have when hearing or reading it. Now, if he said "underwear", I'd be good to go and probably ask him "what the hell are you talking about?"
I am a shy introvert who enjoys the heck out of observing everyone, making all kinds of comments in my head about each and everyone. Yep, some snarky, some nice, I just can't shut off the inner dialogue. And I'm sure my imagination is so much better than what is really going on, anyway.