Honestly the best response is to make it seem they didn’t get under your skin. Some blow off reply like “thanks for your input” and then turn your attention to someone or something else.
I go to a lot of cruises and fortunately have gotten to know a lot of people at the area events, I spend most of my time wandering around checking out other cars and socializing with others rather than camping out in my lawn chair by my car. When I take a break and do sit down, the most common questions I get these days sitting by my car with its repro “1970” license plate is “what year is this car” and lately I get depressed when people keep asking me if I’m the original owner. I tell them no, the only new cars I got when this car was originally sold where Matchbox, Hot Wheels and Corgis because I was 7 years old!