If more happiness = less stress and less stress = more planning, then does more happiness = more planning? Maybe. That, at least, is the equation put forth by psychologist and self-help author Robert Epstein, whose research suggests that 25 percent of our happiness depends on how well we're able to manage stress. Time magazine reports that Epstein's research, which asked 3,000 people how they best manage stress, revealed that the best way to manage stress may be to prevent it, and the best way to prevent it may be to plan ahead. What? Planning is too stressful? Epstein recommends learning some relaxation techniques. Yoga is good, he says, and so is deep abdominal breathing.