Are humans greedy and selfish by nature OR are they naturally good/blank slate?

Humans are naturally greedy/selfish, but some humans aren't as greedy as others. Some of them may not even know that they are greedy or selfish, they naturally are. But some people are happy what they have no matter what, they may have some greed inside of them, but overall they might just be happy with what they have. The people who are greedy and selfish rarely know that they are acting in such way. Sometimes the people who want things may know that they are greedy and selfish, but it's not very likely. Many people, i'm sure, may naturally be nice. They my always have a good side, they are never downers, and they try to look on the bright side of things.