Personally, I think you have to be good, taking into account the variation of the concept for each person, because you can feel comforted, satisfied with yourself, behave in the right way or do something for others, knowing how important this is for your happiness, and many people will value you more. In addition, the people around you can get infected -as well as everything bad sticks- and you would be contributing, in a certain way, to improving the world or, at least, your environment. thanks @robertgenito