When you get called quiet or shy, you get probably even more self-conscious and annoyed. It's like: "I know! Was it necessary to point it out?"
The best way to deal with it, is to appear as if you didn't care about the comment and to regard it as joke. This is the opposite of being defensive and it will make you more respected and raise your status in the interaction.
A simple way to do this is to accept it and justify it funnily. It's a technique from Improv Comedy.
"Yeah, I'm training to be a Buddhist monk"
"I like to play the Silence Game with myself"
How do you respond or how can you respond when people call you Quiet?
Edit: one thing I've noticed in the comments is that many of the responses you guys are coming up with are a bit aggressive and might come off as defensive, and that's not what we want. Don't turn it on them, keep it on you. You're going to be far more appreciated when you don't take yourself too seriously.