Our perceptions and opinions of other people usually have more to do with ourselves than them, since we can only ever speculate about someone else's life. And what do these opinions reveal about us? They expose how we feel about ourselves. Whatever deeply triggers us about another is often an indicator of something we don't like about ourselves. If not the EXACT thing, then certainly the essence of that thing.
Since it is often easier to recognize issues in others than it is to see them in ourselves, if we sit back and quietly observe people, while listening closely to how they talk about others or criticize and complain about the way other people behave, you'll discover a lot about the speaker.
Anytime someone maliciously chastises another, the person making these harsh judgments is revealing that they probably inwardly criticize and ridicule themselves.
So with this awareness, anytime someone attempts to attack you verbally, instead of reacting, taking offense or defending yourself, LISTEN instead to the verbiage they spew.
What are they saying they don't like about you?
What names are they calling you?
What are they accusing you of being? or not being?
Without realizing it, they are telling you oodles about who THEY are and how they feel about themselves - their fears, insecurities, issues, etc.
Remember that ol' childhood line we used to throw back at anyone who called us a name? "What you say, is what you are." Well, turns out there's a great deal of truth to that statement.