Before you act out of impulse, train yourself to remain calm in situations like these. When you’re confronted with unsolicited criticism from people (especially those whom you don’t expect to hear from at all), understand that you don’t control what others have to say about you. Even if you live a life worth emulating, you won’t always get the feedback you think you deserve to hear. You can’t please everyone, and convincing yourself you are an exception will only burn you out. People will always have something to say, that’s just the way it is.