In response to the op:
I personally think that the most of people's meaniness stems from being egoistical and wanting things rather for their own than to see others being successful. There was a guy lately on TV, I'ld type enfp, who wrote a book named "The art of not being an egoist" and that guy was really good, I liked almost everything of what he said. He said that humanity tends to have a sense for unfairness but not for fairness. He said, when having a cushion fight with his 8 year old son and he is in a better position, like standing on a box or the couch, his son will say that the game is unfair. But when they've switched positions and his son is on the couch, the son wont say its unfair again. This is a good example that shows that sensing unfairness is an evolutionary thing and is obviously imprinted in our very gene code. But being fair, everyone has to learn.
If you take a look at our society, you sense unfairness everywhere. It can even make you go mad if you really dig deep into the matter. Food industry for example that wants to minimize their costs everywhere and let kids work for our coffee. There was a good documentation lately on television about Nestle, who buy their beans from Columbia. A reporter made the documentary and showed that you can have a kid to work on your farm for you for $250 on the black market. Nestle commented this with: "We are trieing to work against kid work by spending 4 million dollar per year". If you then know that their yearly turnover is 400 billion, their statement reads like a bad joke.
Another thing we all know of is the expanding gap between the rich and the poor. Some people have so much money they can never spend it. In japan for example there is another morality. It says that when a manager earns more than 1 million dollar a year, he would be considered immorale and would have a lesser standing in society. The reason behind this is to prevent money from being allocated unfairly throughout society and to make a lasting society work, in which everyone can become prosperous to some degree. The western world on the other hand has something like a Forbes Magazine that gives rich people the motivation to even earn more money because they aint no.1 in Forbes yet.
I am personally convinced that the next generation will have a higher morale demand on society itself and will want more fairness. I'll teach my kids fairness and I think this is a thing everyone can do. There are already the first signs on the horizon of a fundamental change in society in Germany. The generation that is my age demand for fair products and clean food not all those readymade sauces or x-ray lunches that have a lot of artificial flavouring compounds or glutamate. People are sich of seeing manager getting paied for failure and getting paid horrendous amounts of money while they themselves earn lesser and lesser. There will be a change, there always will be in a case like that and I hope that after the next revolution, we'll make a better job of teaching our kids the meaning of fairness