In our reality, as harsh as it might sound, a person's worth is measured by their contributions to others. If you offer something to someone, then you worth something to them. If you offer others nothing, then probably you worth nothing to them. All relationships are covered by mutual interests. Which leads us to good and bad people. Good people I think, and in that light, are those who systematically progress their interests while helping others progress their interests, i.e., cooperative people. Bad people are those who systematically try to progress their interests while harming others' interests, i.e., strictly selfish people. Interests could mean anything from feeling good to financial profits. I believe that we are all selfish, but selfish people can be cooperative, and it seems they have to be in order to survive in a stable and fair environment, but at the same time it's the biggest struggle.