Why Some People Are So Selfish?

I don't understand with people who don't have empathy and don't care at all about other people's business. I know they say 'mind your own business' but if you see someone needs help will you just stand still and do nothing just because it isn't your business?
We lived in Indonesia, a country which is known with its nice people. At least that's what foreigner think.
But the fact is there's a bunch of people who still don't know how to behave, careless, and arrogant. Even when they're in public area or in the office. And what make me sad is they're all well-educated people. They only think about themselves and their rights, very selfish. But now i'm kinda usual meeting people like that. In fact, i've met lots of people with different characters. Some of them are truly nice and care to others without expecting anything back. And some of them are being nice only if they want people to do something for them.
So here's a note to myself: it's nice to be important, but it's MORE important to be nice. Have a good day!