“I’ve explained to a number of people my observations about how exercise, diet, and sleep influence mood. The usual reaction is a blank expression followed by a change of topic. No one wants to believe that the formula for happiness is as simple as daydreaming, controlling your schedule, napping, eating right, and being active every day. You’d feel like an idiot for suffering so many unhappy days while not knowing the cure was so accessible. I know from experience that you might accept the idea that daily lifestyle choices are perhaps a small part of what causes your bad moods. But you probably think the majority of your crabbiness is caused by the idiots and sociopaths in your life plus your inexplicable bad luck on any given day. Based on a lifetime of observation, my best estimate is that 80 percent of your mood is based on how your body feels and only 20 percent is based on your genes and your circumstances, particularly your health. Ask”