Pride is essentially comparative, and therefore competitive. Pride is not happy that is has something, only that it has more of it than someone else. We sometimes say that people are proud of being rich, or good looking, but they are not; they are only proud of being richer, or better looking than others. It's the attitude of competition and comparison that is the problem. A man acting out of sexual instinct might bring himself into competition with another man over a woman, but this is only by chance; they might have wanted two separate woman. But a man acting out of pride will take your woman from you, not because he wants her, but because he wants to show that he is the better man.
But by the same attitude you can become quite depressed. Once one starts comparing oneself to others one can start to suffer from low self esteem. This too is a form of pride; it is the man that is unhappy because he has less of something than others. He is unhappy, not because he has no money, or has the appearance of a ghoul, but he doesn't have as much money as he thinks he deserves, as much as others might have, and he isn't as good looking as someone else, and feels that he is less because of it. While the first proud man suffered from an inflated ego, the second suffers from a deflated ego. This second proud man goes to a party and is upset because someone else is the big noise when he himself wanted to be the big noise.
A humble person does not compare themselves to others, and therefore does not compete with others. The humble pianist can enjoy someone else playing a song that he cannot; the humble dancer can enjoy watching a peer perform moves far beyond their ability; the humble gymnast can enjoy his silver medal, not because he has beaten the bronze, but because his routine was enjoyed. A humble person can enjoy life because he can enjoy the success and accomplishments of others. He can enjoy singers hitting high notes without feeling bad about his crummy vocal range, and he can be happy for his friend who earns six figures without feeling bad about being unemployed. Humility is not thinking less of yourself, it is thinking of yourself less.