Two book reviews on happiness are definitely worth your time (ht: A&L Daily).
The first review contains this intriguing quote: "As Jonathan Haidt, a professor of psychology at the University of Virginia, puts it in “The Happiness Hypothesis” (Basic; $26), “bad is stronger than good” is an important principle of design by evolution." This matters a lot--while the reviewer seems to assume that most people in history have been unhappy (an impossible thesis to verify), it is my hunch that the widespread melancholy that afflicts modern America (see: the self-help explosion) is due in part to the adoption of a Darwinian worldview. As Chesterton put it, "The mass of men have been forced to be gay about the little things but sad about the big ones." Such a fragmented approach to life seems to breed cognitive dissonance and a subsequent melancholy. Chesterton's explication of a medieval worldview (see: Orthodoxy) makes it clear they have good reason for gaiety. It's my hunch that their psychology was consistent with their optimistic framework (where "Goodness" is fundamental).
Also interesting is the explication of "positive psychology." A conclusion: "In other words, your happiness consists of how happy you naturally are, plus whatever is going on in your life to affect your happiness, plus a bit of voluntary work. Well, duh. The only vaguely surprising thing about this is how useful voluntary work can be to the person doing it—and even that isn’t really news." Turns out the old philosophers may not have been that far off...