someone once told me the easiest way to detect a narcissist (not to be confuse with someone who has some narcissistic traits because many people do and it doesn't mean they are a narcissist) looks like this as their behavior:

normal people:

i win, you win

i win, you lose

i lose, you win

i lose, you lose

narcissists:

i win, you lose

i win, you win

i lose, you lose

i lose, you win

narcissists tend to want to burn and lose everything rather than let you win. people without NPD don't do that. everyone likes to win a little, meaning everyone has some narcissistic TRAITS but it is not the same as having NPD. once you recognize this and see constant patterns in people, it is easier to detect who is an actual narcissist and needs help and who just has some traits.

the word narcissist gets thrown around so much these days likely because a lot of normal and healthy people have traits. NPD is not as common as people make it seem and making it seem common is making it easier for actual narcissists to hide and fly under the radar (dangerous).

(also this article is spot on and i agree with it)