Why do some people always seem happy, and others not? Is it really a question of life circumstances? Are they happy because their life is better, because they have more luck, and they just don't have as many worries and upsets?

Or is it more a question of disposition, their nature, and character? Could it be that some people are genetically wired to be happy no matter what?

People who are highly satisfied with their lives are less likely to have psychological or social problems, less likely to get sick or be stressed out, and more likely to do well at work.