Narcissism is a personality disorder in certain people that makes them seek endless approval and attention.
Their deep distortion of sense of self makes them disloyal, manipulative, deceptive and domineering. You simply cannot take them at face value and they never apologize.
Now, if this describes someone you know in any way, you need to stay as far away from this person as you can because he or she only views you as a potential threat or victim. It’s just who they are.