Man’s uniqueness lies in his ability to feel others because he is filled with envy and jealousy, craves for wealth, fame, power, knowledge, and everything else that his society is obliged to provide him with.
An animal is content with what it has and its actions are instinctive. In contrast to animals, man cannot be satisfied with what he has. He is created in such a way that he will find peace only if he owns everything that everyone else can possibly possess. By looking at others a person acquires their desires. This envy happens to be the principal driving force of our evolution.
Courtesy of http://www.youtube.com/watch?v=KZvL2N0bXhE