It is hard to understand why Red Sox fans care so much about tonight’s game. But we do. I’m ashamed of it and can’t fully explain it. I’m ashamed of it because nothing truly rides on the outcome. And that makes it hard to explain. How strange it is to suffer and feel joy over some strangers hitting a ball with a stick against other stangers. One explanation is dopamine, the chemical your brain experiences  for an unexpected reward. Is there any reward more unexpected than a Red Sox defeat of the Yankees? In this theory, losing to the Yankees is simply an investment in an even greater reward when the Red Sox eventually win. So we root for the Red Sox for that rare but enormous payoff. In this explanation, rooting for the Red Sox is like playing the slots in Vegas or buying a lottery ticket. Someone wise in the ways of baseball and bureaucracies once said that when the Red Sox win the World Series, it will make a Yankees World Series celebration look like a day at the DMV.
My small attempt to understand it without invoking neurotransmitters is here .