Valentine had long ago observed that in a society that expected chastity and fidelity, like Lusitania, the adolescents who controlled and channeled their youthful passions were the ones who grew up to be both strong and civilized. Adolescents in such a community who were either too weak to control themselves or too contemptuous of society's norms to try usually ended up being either sheep or wolves- either mindless members of the herd or predators who took what they could and gave nothing.
Orson Scott CardAn enemy, Ender Wiggin," whispered the old man. "I am your enemy, the first one you've ever had who was smarter than you. There is no teacher but the enemy. No one but the enemy will tell you what the enemy is going to do. No one but the enemy will ever teach you how to destroy and conquer. Only the enemy shows you where you are weak. Only the enemy tells you where he is strong. And the rules of the game are what you can do to him and what you can stop him from doing to you. I am your enemy from now on. From now on I am your teacher.
Orson Scott Card