Probably one of my top pet peeves: If I say "no thank you" or "I'm not interested in X" and person keeps pushing whatever X is constantly and doesn't listen to me saying no.

This will make me very annoyed and upset. No means no. Just stop. It's not cute or funny. It's disrespectful and rude.

Calling this a pet peeve is probably not even right. I just hate this behavior.