Hey, I feel for ya. There's nothing I enjoy more than cranking up the stereo in my car and listening to my whacky music. (Bagpipes, banjos, Irish drinking music, you name it and chances are I have it.) It's actually one of the few things that I can actually without worrying about what other people think. I do turn a few heads, but it's all good.
Just something to think about that might make it a little easier.
What are the odds that you'll see that person in the car next to you again? Probably pretty slim. So why does it matter to you what they think? Unless it's the cops, and even then they didn't seem to care, Screw 'em and crank up your stereo. I know it sounds hard to do (it sounded hard for me too when a guy I met at school told me to "f--- 'em,"
but it's getting a lot easier as the days go by.
Keep your chin up.