Most people never see the distinction or correlation to the fact that they are getting back exactly what they are putting out into the world.
If you decide to start gossiping about someone, stealing, spying, cheating, being jealous, becoming easily frustrated or angry, having impatience, looking down on someone else, or taking actionable revenge on someone… then you have no right to be surprised when Karma comes around and hits you with the same stuff twice as hard.
Also, if you decide to walk that dark path, you will start to lose the good people in your life, as they will gradually distance themselves from you. All you will have left as friends (that are fake now) will be other gossipers, liars, cheaters, and other people who confuse emotional revenge for justice.