not let other people's negativity bother me so much

Specifically one chick at work. She antagonizes almost everyone because she’s always in a sour mood. I’m tired of caring what other people think so much. People who have bad attitudes and want to bring everyone else down with them. I wish I could just go about the day, ignore them, and be merry. But instead I take it to heart and let it get me down. I’ve always been like that, but I’m gonna work on it! Let it roll off my back and realize that that’s just the way some people are and you have to let them be them while you stay your positive self!