From a New York Times column by David Brooks headlined “The Self-Destructive Effects of Progressive Sadness”:

One well-established finding of social science research is that conservatives report being happier than liberals. Over the years, researchers have come up with a bunch of theories to explain this phenomenon.

The first explanation is that conservatives are more likely to take part in the activities that are linked to personal happiness — like being married and actively participating in a religious community. The second explanation is that of course conservatives are happier; they are by definition more satisfied with the established order of things.