Narcissists often try to dim your light because they feel threatened by your confidence, success, or positive qualities. They may harbor deep-seated insecurities and a fragile sense of self-esteem, leading them to perceive your accomplishments or happiness as a challenge to their own self-image. In an attempt to regain a sense of control and superiority, narcissists may engage in behaviors aimed at belittling your achievements, undermining your self-confidence, or taking credit for your successes. By dimming your light, they seek to maintain their perceived dominance and inflate their own ego.
My Voice Unchained 