Man is the only creature who refuses to be what he is...

Pride, then, seems to be a sort of crown of the virtues; for it makes them greater, and it is not found without them.
- Aristotle, Nicomachean Ethics, c. 350 B.C.

Aristotle’s philosophy was the intellect’s Declaration of Independence... For Aristotle, the good life is one of personal self-fulfilment. The man should enjoy the values of this world. Using his mind to the fullest, each man should work to achieve his own happiness here on earth. And in the process, he should be conscious of his own value. Pride, writes Aristotle—a rational pride in oneself and in one’s moral character—is, when it is earned, the “crown of the virtues.”

A proud man does not negate his own identity. He does not sink selflessly into the community. He is not a promising subject for the Platonic state. 

Courtesy -> http://aynrandlexicon.com/lexicon/aristotle.html