In fact, this is what they mean when they say it's almost impossible to know who the real sociopaths are. The true ones are so charismatic and good at manipulation that, unless you are extraordinarily close to them or get on their bad side, they just seem like the sort of person that everyone likes.

Interestingly, a minority of people seem to be somewhat able to see through the facade. I have ADHD and a brother who's very nearly on the autism spectrum, and both of those conditions seem correlated with this ability to have an unbiased sense of a person. Perhaps it's due to the way we are slightly detached from normal social interactions, or the highly analytical way our brains function. All I know is that there are definitely times I feel this. For instance, if you look online, there are tons of relatively recent videos that have special forces types (SEALS, rangers, etc.) commenting on movie scenes or so on. The comments are always full of people talking about how they seem like such a great person, or how funny/charming/positive/etc. this person is. Meanwhile, I just come away with this feeling of being very deeply unsettled by them almost every time. Everything about their demeanor unsettles me. Now I'm in no way saying every special forces operator is a closet sociopath. But the job does attract a certain personality type, and many of the ones on these videos are the most charismatic of the whole bunch.

Back on topic, John always seemed to be to be a pretty typical narcissist to me. He did some stuff that I found to be funny in kind of a black humor sense (that video of him supposedly telling you how to uninstall McAfee antivirus), but the idea that he was a truly positive person I just totally don't see. I mean, think about it -- the OP's story involves John having the guy call his wife and tell him how great he thought John was and how great his ideas were. That's pretty typical narcissistic behavior.