I think what surprises people is not so much the idea that walking improves your mood as the idea that your mood dramatically affects your happiness. People ten

I think what surprises people is not so much the idea that walking improves your mood as the idea that your mood dramatically affects your happiness. People tend to think of happiness as a profound, grand-scheme-of-things thing. But here's a thought experiment: take a person in almost any living situation and make it so that whatever his circumstance, his minute-to-minute mood is always happy. How unhappy could such a person be? The other reason it's surprising, I think, is that while being indoors all day sucks, it's a kind of suckage you don't realize till it's fixed. When I used to stay indoors all day, I'd find myself constantly in a bad mood but not know why. It's kind of like socializing for introverts. As an immature introvert I didn't think I needed social interaction till I was virtually starved of it.