Here's even more identifying ways to figure out if you are dealing with an S or just a crazy normal person.
The following is an excerpt from Thomas Sheridan Arts that I think is a pretty fantastic and comprehensive list of ways to identify a Sociopath. His entire website is a great source of information, so if you like this, give his other stuff a glance.
If you experienced the following behaviour while in a relationship, or working with this person—then you probably knew a psychopath:
Invented Personas to Manipulate Others
Psychopaths are a different version of themselves for every person they interact with. They also have ‘group personas’ for family, organisational and workplace interaction.
Highly Unreliable/Broken Promises
Psychopaths will make the most incredibly ambitious plans including you as their right hand man or woman—then, on a whim, discard those plans and move on to some other crusade that excludes you. Targets often alter their own life plans to help the psychopath reach their imaginary goals, resulting in appalling emotional, psychological and financial chaos for the victims when the psychopath moves on.
Idealisation Followed by Cold Rejection
At the height of their idealisation of you, the psychopath will show you obsessive ‘love,’ care and attention. However, once they feel they have you where they want you—or the relationship has ended—if you collapsed in front of them on the street they would simply step over you as if they’d never met you and continue on their way. Outrageous and very personal smear campaigns against the discarded targets to falsely portray them as psychologically unstable, self-serving liars or abusers are often undertaken by psychopaths following the ending of a relationship.
Becomes Obsessed with a Hobby, Cause, or Individual and then Loses Interest Instantly
However, as soon as the relationship is established, the downward trajectory from idealisation of their targets and towards the inevitable devaluation and discarding begins in earnest. It may take weeks. It may take months. It often takes years. Nevertheless the psychopath always begins the devaluing of their victims as soon as the relationship is legitimised and is always on the lookout for an ‘upgrade’.
Buys into either secular and non-secular belief systems to appear superior or enlightened. Will align themselves with ‘morally popular’ causes to make themselves appear enlightened and with a sense of deep moral wisdom and compassion. But it is always a pose; the psychopath’s association with these causes is a veneer to fool others into trusting them. It’s always fake; always an agenda.
There is Nothing Real Behind the Persona
Behind the months or years of perfectly-constructed performance by your psychopath is a nothing: a void, a blank, a hunger for something the psychopathic entity can never define. They now see no further benefit in playing this part and have moved on to a new role. It is just business. You are treated to a completely new, cold and emotionless persona. “Who is this stranger?” you will ask yourself over and over again. It is so bewildering.
The Sudden Goodbye
Then the psychopath finds an upgrade, changes their persona, will often change their look, fashions and even change the subject when they suspect others are figuring them out and you begin asking questions. "Hey, never mind that, it is lovely weather we are having!" Stated in a chipper and almost giddy manner (with an obvious underlying glibness). They are repressing the internal excitement at having pulled a fast one on you.