tintoy deserting a friend in a foreign country, and then finding it hilarious is definitely the sort of thing a psychopath would do. Can't imagine a) a normal person even thinking of doing this, and b) then finding it funny after they've done it.
I definitely know of two psychopaths, both of whom, chillingly, had absolutely no remorse for their actions, and no conscience. As a psychologist friend said, having absolutely no conscience is a dead giveaway. Not talking about the occassional slip a normal person might have, btw.
The last psychopath I worked for was in charge of our department. He had two women who were pregnant at the same time. The first woman was a long-time employee of his. However, because he did not want to pay maternity benefits to the second woman, he targeted her quite ruthlessly. The second woman was a stellar performer, and he would send her appalling emails, block her in her job, hand over her responsibilities to others etc etc, when she was 7 months pregnant, and having issues with the pregnancy. I believe he was actually happy to break the law (as long as it suited him, and he wasn't caught), and he had a remorseless twunt as a manager who supported him.
The other psycho I encountered took great pleasure in taking advantage of me when I had to have life-saving surgery, then bad-mouthing me to friends and turning a whole group of people against me when I was trying to recover from above surgery. Later, I also found she tried to convince another friend to hand over her 10yr old daughter's pony to the psycho's daughter! Friend's daughter was absolutely distraught! Piece of work that psycho was!