> The biggest signal of narcissism: Inability to take feedback constructively. Unless they've been somewhat socialized for professional behavior, narcissists tend to react explosively and aggressively at anything other than praise.
Depends on the culture and situation.
First: What's at stake with the "feedback"? Is this a peer trying to help you? Or is this a hostile boss, and is the "feedback" part of a "performance management" process? You can call something "feedback" all you want; context and intentions matter.
(As a mostly-harmless demonstration, I was tempted to play a game here where I just quoted your sentence "The biggest signal of narcissism: Inability to take feedback constructively" and then wrote "I think this post is pretty bad" right after it. Then, assuming you attempted to defend yourself, I would have been able to point to those defensive behaviors as "narcissism". And, if in the face of that accusation you again defended yourself, I could then double down. I'm not going to troll like that, but you see the dynamic you can set up this way. Recognizing this, I am skeptical of people who wave these words around. That said, it's also clear that, when there's as much money around as there is in Silicon Valley, there are going to be people you need to defend yourself against, so I won't discount the idea entirely.)
Second: How will your response be interpreted? Are you working with someone who has your best interests at heart? Then recognize that they're trying to help you, and of course appreciate that they're taking the personal risk with you of offering criticism. Or are you instead in an adversarial situation -- think the justice system -- where a failure to argue your case is seen as an admission of guilt? That again matters. Then -- don't lose emotional control -- but also don't just roll over.
> A secondary signal of narcissism: Always having to be "right", usually by gaslighting the other person or slippery lawyering.
I think this stems from perceptions about the consequences of being wrong. For example, at Amazon, they say something like "leaders are people who tend to be right". And of course, being a "leader" comes with financial rewards. So of course you'll want to avoid the perception that you're "wrong" in that environment. But the problem is as much the toxic environment -- intentionally set up by leadership -- as it is the personalities of the workers who've been thrown into the Hunger Games against each other.
One of the things that concerns me about these psychological weapons -- like, the labeling of another person as "narcissistic" -- is that they seem like they can just as easily be used against the innocent as against the deserving. In particular, when people in positions of authority wave these words around in reference to underlings, it can just mean "don't know their place". I have heard, for example, that when patients demonstrate knowledge of their conditions (or worse, push back, ask for second opinions, and so on), doctors sometimes label them as "narcissistic". I'm skeptical that "failure to defer to me" is necessarily a personality defect.
I would offer another way of thinking about things: Does the person stay out of other people's psychological space? Do they try not to work against others' material interests? Do they engage in more win-win or more zero-sum interactions? An idea like that seems less likely to be abused to me.
I'm also a little wary of the binaristic trend I see in these labels: People are classified as "being dark triad personalities" or not. I feel you're probably going to be more humane if you see shades of gray.
That said, all this means that I do agree with you when you write:
> I always see more psychopath-tendencies/assholes associated with MAANG megacorps
I agree that those environments bring out the worst in people. But I think it's as much about the environment as it is some inherent feature of the people who end up in those jobs.