According to various people, they have different level of self-esteem because they different feeling of worthiness to themselves. Somebody like a cleaner or a normal citizen does not feel they are worth that much. For example, a cleaner will think "oh even if I quit the company I am working for, it will just find another one to replace me." This presents he/she does not think she is worthy, thus he/she will have low self-esteem. But others like president of a country or a boss of a company, compared to a cleaner, have a higher level of self-esteem. President will think that "I am the leader of this country, the country cannot function without me!" This shows that he/she feels high worthiness because he/she thinks the country will be in chaos without him/her.
Despite the workplace position can affect one's sense of worth, individual's mind is the most crucial because the "sense of worth" is totally subjective. A cleaner can think like the President that "If I am not here, there will be no one to take care of this place. I am very important here." or the President will think like the cleaner that "I am so useless, I cannot lead this country well."
Self-esteem is about worthiness. If one feels worthy, he/she will have high self-esteem, and vice versa.