Happiest countries in the world are all atheists majorities, how come?

Happiness? How in the world do you define that? How in the world do you measure that? Across so many different cultures? Atheism, I doubt has anything to do with it. That's what i believe is referred to as a statistical anomaly. I think people who live freely would consider themsleves happy. I know America would be least happy for reasons only relating to religion (eg, capitalism, consumerism, Americanism, twitterism, etc).