Cause they only focus on themselves? If that gets attacked, it’s an attack on their only asset. When your focus lies on a spectrum of interests other than yourself, you keep an overview and your overall self worth. I dunno.

Hmmm… That gives me an idea.

I know someone who might be a narcissist. Maybe I could exploit this vulnerability to expose him. You know, just to test my suspicions. Could just say something that mildly challenges his ego and see how he responds. If he menages to keep his cool like a normal person, then my hypothesis was wrong and I don’t have to be so suspicious of him any more.

Careful. Skillful Narcissists can be quite adept at keeping their cool in public (to maintain their positive public image) while simultaneously planning their complete and total revenge on you - smear campaign, sabotaging relationships, setting up traps, lobbing false accusations, messing with your employment, messing with your spouse, vexatious lawsuits, the works.

If you play with a Narcissist, be prepared to go ALL THE WAY when you dance with them. Complete and total WARFARE.

Really, unless you have some compelling reason to do so, the only winning move is not to play.