Opower sends hard copy letters to people in a neighborhood. Letters don't just say, hey, other people in your neighborhood are trying to conserve energy. This has been studied extensively by lots of economists that I really respect and admire. So look, that's a really clear case for envy for good. Go envy.
What does social media do to our self-esteem? How is envy affecting our politics? And should you go to your high school reunion?
Take the Seven Deadly Sins survey: freakonomics.com/nsq-sins/