Rabbi Yerucham Levovitz said, "When someone insults you, even for selfish reasons, do not automatically disregard what he says. Rather, check yourself to see if there is any aspect of truth, regardless of his intention, and try to learn from it."

For example, if someone says you are "lazy," instead of becoming upset, use this as a motivation to overcome some aspect of laziness you do have. Even though you are usually not lazy, you can still improve.