Welcome to MT!
I used to get asked the question "Can you beat up____?" Just insert any random person's name in there. I also had some people do a "mock" karate kid crane pose around me or do a mock kata.
I found that some people think I'm a killing machine, some people think what I do is a joke, some people think what I do is cultish for some reason, and rarely I get a person's respect for it. Which gives me some hope for the future.
I've gotten that one too - along with various friends introducing me as their bodyguard (funny now, but not at the time).
I quit telling the middle school students I teach about it because I got tired of being asked if I could break a desk - my stock response was "I don't know - do you have $80?" which worked until one kid offered to come up with it. Bearing in mind that these are typical school desks, made of inch-thick particle board, covered with laminate, and supported by a metal bar... not even going to think about trying it. But a few coworkers who've seen me train think they know why I have so few behavior problems in my classes - they're wrong about the reason, right about the source, as it's nothing physical; I treat my middle school students with the same respect as my TKD students, and it comes back from both groups.