When I was a kid, generally "Animal Freak!" or "Science Nerd!" were the reactions of choice. Now that I work in a museum though, I tend to just get people asking me more questions. This goes on for an hour sometimes, or however long the visitor wants to stick around. It's actually quite nice.
No one really bothered me about my art interests, well except for my mother, who loved that I wanted to do that all day. She became obsessed with training me up to be a "real" artist one day.

...and then I ended up illustrating comic books. Poor Mom.
Hmmm, as for karate, my boyfriend sometimes has to grab my shoulders gently and say "Okay, time to separate karate from personal life." The first time I was surprised, but then when I thought about it, I realized that I had been talking about the history of karate in Okinawa on and off for several hours.... whoops!
And lastly music. Usually not many people complain about that until I've continued playing my flutes or singing Broadway songs too late into the night. Mostly I just obsess over that in my own mind. A private symphony 24/7.
Lucky! Being a comic book artist would be a dream come true for me! My mom would be proud of me if that happened! Not that she doesn't already take (misguided) pride in the (crappy) fanart I do for the shows/movies I obsess over...