Liking pop music. I'm not saying every guy that listens to pop music is gay, but most gay guys listen to pop music. Try to find a gay male that listens to absolutely no pop music at all. It's practically impossible
Stereotypes have a kernal of truth. They're useful for broad categories but it's important to remember individuals are just that - individuals. To believe everyone fits into a certain stereotype 100% is ignoring that everyone is different.
I'd say that gay stereotypes have a level of accuracy, but at the end of the day you should treat a person like a person and not a stereotype.
I also feel that people think fitting a stereotype is a bad thing - imo it's not as long as you're being your authentic self. I find it annoying when people intentionally follow a stereotype because they think they should.