Ah, narcissists. Checking themselves out in every reflective surface they walk by. Yammering on about that one time they won the third-grade spelling bee. Thinking they’re God’s gift to the universe—after all, why else would He have put them right in the middle of it?

But here’s the thing: Narcissism is way more complex and, quite frankly, way more annoying than that.

Yes, it’s an inflated sense of self-importance and a hankering for constant admiration, combined with a devastating lack of empat...