As a little boy, the first thing you learn about life is that you will always be stronger when you are part of a team. After all, we are pack animals; it is how we have survived this long. People are not hard-wired with this sense of community because we enjoy it, but because it is necessary.
Popular sports mimic the hunt, the battle, the war, in one way or another. It represents execution of strategy; working together to outsmart, outplay, and out hustle the other guys in the different color uniforms. Finding the best use of your power and focusing it collectively where it can do the most damage to your opponent is the heart of team sports, and is the soul of war.