I always reference professor Sam Vankin in regards to narcissism often. A person has to have 2 different faces because their personality is contingent upon whoever they're standing in front of. Many times it has to do with how they are benefiting from whatever party they're standing in front of .
Sadly if you have nothing to offer, you don't even exist for people like this. Be sure to listen to the bonus episode of my podcast above. I detail a personal experience in which an older lady proceeded to use narcissistic tactics to keep her position in any organization.
