No man when he views the lot of others is content with his own. This is why we grow angry even at the gods, because some person is ahead of us, forgetting how many men there are behind us, and how huge a mass of envy follows at the back of him who envies but a few. Nevertheless such is the presumptuousness of men that, although they may have received much, they count it an injury that they might have received more. Seneca, On Anger 3.31.1
