Possibly part of the problem is that we live in a very competitive world. We exalt sports figures and heroes for instance… always praising and adoring the ‘winners.’ There always has to be a winner and a loser. Sports winners and losers are broadcast on the news every day.
Part of it may be just greed and jealousy, too… people who want power and attention and aren’t happy if they don’t get what they want. Some people just seem more ‘needy’ than others. They will sometimes do anything to get power and attention, even if they have to lie, cheat and steal to get it, and of course that creates a lot problems. I do think that people (and even dogs and other animals/pets) are often born with different personalities and tendencies, so likely it is in the DNA, too.