Finding out that Darth Vader is Luke Skywalker’s father probably didn’t have any practical implications for your life. It didn’t translate into a raise at work or help you lose 15 pounds. So why do we care so much about the fates of fictional characters? William Flesch is the author of the book “Comeuppance: Costly Signaling, Altruistic Punishment, and Other Biological Components of Fiction.” He argues that we root for good guys and gals because we love making bets on people. And, once we make those bets, it’s imperative that we are proven right.