" As the popular saying among scientists goes: genes load the gun; the environment pulls the trigger. The exact same traits could easily be put to use in more or less devious ways. The choice is not predetermined. And the presence of Machiavellianism or psychopathy or narcissism no more marks someone as a grifter than the presence of charisma or nonchalance. "

― Maria Konnikova , The Confidence Game: Why We Fall for It . . . Every Time