Your definition of success and their definition of happiness might be in conflict.

For example, they might be comparing themselves to you, and if you succeeded, they might come to feel ‘not good enough’ due to their conditioning. It is a very common aspect of many of the cultures of the world to define the worth of a person by their status in the world in comparison to other human beings, how successful they are in terms of the possession of things or achievement of certain goals. So, most people are conditioned to feel unworthy unless they are successful according to such criteria. And people who fulfill these criteria become a reason to make them feel unworthy in their minds because of this conditioning. So, they want to undermine them, or don’t want them to succeed.

Sometimes the criteria put forth by the culture is such that people are driven towards the same goals, such as possessing more and more money, or objects or control over other people. This creates conflict of interests and induces hostile competition for the same ‘resources’ that are believed to give happiness.

If people were taught to experience their intrinsic worth from the beginning or if they all awakened to it, these patterns of greed, jealousy, hostility would cease in the world because another person’s achievements can not destroy the experience of intrinsic worth of a person.

Two persons who are both experiencing unconditional love can find ways to cooperate and not undermine each other because for such people happiness is intrinsic, not tied to what they own or achieve, but coming from within themselves and they are aware of this.

The root reason therefore is the unawareness of people of their true nature, and the conditioning by the society that distorts their perception to believe that they are unworthy as they are and can become worthy only if they fulfill certain criteria, which leads them into comparison and hostile competition with other people.