In response to a previous comment, narcissists are envious and jealous of you and they want you to fail. Covertly they do what they can to sabotage you. This can be quite bizarre because you likely have some sort of relationship with them where you assume they're on your side and want what's best for you. The protagonist in The Count of Monte Cristo has his life turned upside down by the envious scheming of a "friend" who was a narc.
I'm clarifying because without direct experience or learned understanding, many wrongly assume this word as it's being used in the psyche videos refers to mere self-absorption and selfishness. Instead it refers to calculated evil.