How do psychopaths behave?

By acting like the exact opposite of what they are, by being as kind as angels. Generous and morally rightous individuals. They can even be popular. Sometimes they can be your friend for years, sometimes the only give away is when they do something profoundly wrong and then ask for your pity instead of trying to make the problem right. Dont give someone your pity if they are going to use it against you. Remeber these people could torture an animal to death for fun. Which means they could torture you to death for fun.