I think there are a number of things we probably should be careful about when assessing people and/or "following" what they say and do. For example, I personally think there are a number of serious "red flags" I tend to be careful about that raise alarm bells for me as soon as I notice them. For example, when somebody has shown behaviors that tell me that something in the character of a person could very well be seriously wrong, indecent and/or bad. Yes, there are many things most if not all people including pathological and not pathological people can say or do that are bad, but some things for me are just so extreme and indecent and sort of revealing of the sort of character a person has, that I tend to be very careful and critical about them ever after.
In Nicks case for example, even though, as said, I just recently discovered that this guy even exists, a number of the things I heard and have seen about and from him since then immediately put me on guard, and I wasn't really interested in following him, and instead I decided to stick to other people. A number of those (what could maybe be called) serious character flaws, that caught my attention, are: Apparently joking and/or making allusions to pedophilia being not so bad. Secondly, he seems to have not so many problems with betrayal in one way or the other, for example, betrayal of trust. Thirdly, he seems to have little problems misbehaving in someone else's house, or more correctly, play decent in someone else's house and towards the people there and then turn around and throw them under the bus. Fourthly, he seems to have a pretty strange/indecent and probably pathological view of woman.
Some things a person can do or say just point to a pretty rotten personality/character to me, and it raises alarm bells. When some people say or do certain things that just seem to be so rotten, I tend to be careful. And I don't think a rotten character necessarily has to be a Psychopath, either. There can be many reasons for that, but what it tells me is that there is a good likelihood that something might be rotten with the personality/character of that person. Better be safe than sorry. If you think about it, there are a number of things a person can say and/or do that not even half decent person would probably ever say or do. And also, I think, even if we account for people being able to change positively over time, there are just a number of things that are so rotten, that I think, generally speaking, it is very hard and/or unlikely that a person that displays such characteristics can significantly change over a lifetime. It is always good to give people the benefit of a doubt and also give the idea credence that people can change to the positive over time, but when a person has displayed rather extreme forms of what I would call rotten behaviors I will be on guard as well and also assume the likelihood that the person has not changed, or maybe, not enough to be in the decent range.