the world isnt just and people are not made equal, a lot of us are born without enough desirable/positive qualities to be considered useful by society. And really, that's why we can't be happy- because we are not useful, neither in the workplace nor in social relationships. If you're surgeon you make people happy, if you're charming you make people happy even if you're a neet. So people give back to you, people make you happy in turn.