Have you ever met a psychopath?

For the past month, I have been reading "The Wisdom of Psychopaths" by Kevin Dutton which delves into traits, behaviors, and motivations behind psychopaths. This book isn't just about serial killers but rather also the "successful" functional psychopaths such as stockbrokers, politicians, and business executives. You can read an excerpt from the book here if interested. A few interesting takeaways that I have had from the book so far are the innate cues that some people have on picking up on psychopathic cues. This is like speaking to someone and getting the heebie-jeebies from them for some reason. Apparently, women are more perceptive to this than men.

So, I'm curious if you have ever met a person that gave off that vibe, and what in particular gave you that vibe?