Marginal Revolution: Blink

"In one study we were watching newlyweds, and what often happened with the couples who ended up in divorce is that when one partner would ask for credit, the other spouse wouldn't give it. And with the happier couples, the spouse would hear it and say, 'You're right.' That stood out...for a marriage to survive, the ratio of positive to negative emotion in a given encounter has to be at least five to one."