Republicans are happier.

No surprise there. Surfing the right and left sites will tell you that. But Powerline has this:

One of the things tracked by the Pew Research Center is happiness. Since the 1970s, the Pew pollsters have been asking Americans how happy they are and analyzing the results. This year's survey came out on Monday, and, as always, it shows that Republicans, on the average, are happier than Democrats:
Some 45% of all Republicans report being very happy, compared with just 30% of Democrats and 29% of independents. This finding has also been around a long time; Republicans have been happier than Democrats every year since the General Social Survey began taking its measurements in 1972.