כל המעביר על מדותיו מעבירין לו על כל פשעיו
.ראש השנה יז
According to the level that the person forgives those who hurt him, Hashem will forgive his sins. Sometimes a person reacts to the insult but eventually forgives, other times a person might not react to the insult at all but he carries a negative feeling about the episode. The best is when a person totally erases any negativity; then he’ll merit for his sins to be fully erased.