You can see why the Greeks cared so much about war- and why we care so much about it too. We need some way to measure ourselves, to show mastery over the physical, material world. We don’t really have much control in life- over death, aging, finances, love- and so when we have a controlled environment, like a football game, with a definite metric for victory- we take it extremely seriously. Why? Just because we can take it seriously. Because everyone else in the game will take it seriously- and because no one else is watching to tell us we’re stupid.