Most of us live in a hierarchical system with infinite levels. In these, we are easily made unhappy by those who have a little more status than ourselves.
Regardless of whether we are at the bottom or higher up, there is always someone above us in the pecking order who got there a little faster and a little easier. These hierarchies make it harder to be satisfied with what you have. A solution might be to compete with yourself and accept that you are doing the best you can. After all, one's most important value does not consist in our status or our achievements, but in the fact that we are human beings and preferably fellow human beings. Then we should create more egalitarian organizations where everyone is needed and everyone is equally valuable.