Question about certain personalities!!!!

Why is it that some people are so full of envy? I mean, they try to belittle or even bully people that they are envious of. I love to watch and analyse people's behaviour. For example, some people never stop talking about other people. Every conversation has to be about other people. There are some people that are so full of hatred that they manipulate others to hate you too with false stories about you. If there is anything that I dislike in people, it is the spirit of manipulation and bearing false witness against others. Some people even make up stories about others in their small minds and really believe it. They make sure that other innocent people get a taste of their poisonous tongues. I really don't allow myself to get too close to nosey people who use stories about you to make friends or make themselves seem important. My question is, can such people ever change for the better and do they really know that they are hurting other people or are they so consumed in their own selfishness?