My girlfriend is a very friendly person who can also become petty and mean when she feels she has been hurt. The other day a former friend—who’d been condescending to her and ended their friendship—came up in conversation, and she started ranting about all the “random people” this person has slept with and got very short-tempered with a friend who tried to calm her down. I find it embarrassing that she continues to be so hot-headed about minor things. Sometimes I tell her she’s being mean and should stop, and she just gets angry at me. Is this actually an issue or am I just being controlling and need to let it go?