It's good that you don't take it personally, sometimes you just gotta smile to yourself because you know they are missing a good thing.
During high school I started in on fish keeping. I had tanks from 10 gallons to 30 gallons in my room- even got my dad into fish keeping. But I kept it to myself for the most part, just for that reason- people don't understand the joy of fish keeping if they don't experience it themselves usually, as well as some kids are just plain rude.
My boyfriend teases me about my bettas- he's a fish person, but cichlids and saltwater, and he doesn't understand how bettas can be addicting. He'll tease me about them, but he'll grin and bear it when I'm in a chatty mood about one or the other. I've learned that if I give him a massage, I can talk about the bettas all I want, and if I'm lucky, talk him into letting me bring in another :P But other then that, I don't talk about them to many others.. to a lot of people fish are "just fish".