Envy is also a question of attitude. Whenever we come across someone who is better or more successful than we are, we can react with indifference, joy, admiration, envy, or emulation.
Envy is the pain that we feel because others have good things, whereas emulation is the pain that we feel because we ourselves do not have them.
This is a subtle but critical difference. By reacting with envy, we prevent ourselves from learning from those who know or understand more than we do, and thereby condemn ourselves to stagnation. But by reacting with emulation, we can ask to be taught, and, through learning, improve our lot. Unlike envy, which is sterile at best and self-defeating at worst, emulation enables us to grow and, in growing, to acquire the advantages that would otherwise have incited our envy.
Why can some people rise to emulation, while most seem limited to envy? In the Rhetoric, Aristotle says that emulation is felt most of all by those who believe themselves to deserve certain good things that they do not yet have, and most keenly by those with an honourable or noble disposition. In other words, whether we react with envy or emulation is a function of our self-esteem.
Adapted from Heaven and Hell: The Psychology of the Emotions