This map shows levels of "subjective well-being" around the world - i.e., how happy people say they are. A couple of thoughts on this:
First, just from eyeballing this map, it looks like there is a correlation between national wealth and general happiness, but not an exceptionally strong one. Most developed countries rate quite happy, while many poor countries, especially in Africa, rate relatively unhappy. But still - Guatemalans are happier than the French; Mongolians are happier than the Japanese; Kyrgyzstanis are happier than Russians. (And notice our Bhutanese friends seem pretty content - their GNH policy must be working.)
Second, I've long felt that once an individual (or a society) reaches a certain degree of wealth at which their basic needs - food, shelter, medical care, maybe education (i.e., everything that's fairly low on Maslow's hierarchy of needs) - that all further wealth has relatively low marginal utility. That is, if your basic needs are taken care of and you don't have to worry about them much, then non-wealth factors will have a much greater effect on your overall level of happiness. I think this map bears that out. While some regions, such as much of Africa and South Asia, are clearly unhappier than others, these are regions where basic needs are oftentimes not being met. (Most of the former Soviet Union also appears to be in a grim mood, as well, though this might be attributable to their particular sociohistorical legacy.) But if you look only at middle- and upper-income nations, I don't really see a discernible difference. Countries like Malaysia, Costa Rica, and Saudi Arabia are among the happiest in the world; Thailand and Colombia are comparable to France and Germany; etc. So if I were a nation, what I'd be trying to do is encourage economic growth to the point of achieving middle-income status, and once that goal is achieved, devoting additional resources to ensuring that the basic needs of all my citizens are met. (Of course, the premise of such a policy would be that happiness is inherently more valuable than pure economic power, and some might disagree with that.)
Third, though: I wonder how seriously any of this ought to be taken. People are not necessarily entirely reliable when it comes to reporting their own mental states. Depending on the methodology by which this data was compiled, it seems possible that cultural conditions or expectations influenced the way people reported their own feelings, regardless of what their actual feelings were. For instance, Anglophone countries all reported fairly high levels of happiness. Is this because Anglophone people are happier - or did the wording of the question have a particular connotation in English which was different from other languages? Or is there a legacy of the peculiarly Anglo "stiff upper lip" such that Anglophone peoples felt they ought to say they were happy, regardless of how they actually felt? Similarly, most Buddhist countries scored relatively high (again, including Bhutan). This could be because Buddhists tend to be happier - or it could be because Buddhists feel it's more important to report that they're happy. Because I think it's impossible to know which it is for sure, I would take this map with a medium-large grain of salt.
On the other hand - the French are the grumpiest people in Western Europe? Sounds about right to me.
UPDATE: Here's a snippet from a BBC article on the map:
Adrian White, from the UK's University of Leicester, used the responses of 80,000 people worldwide to map out subjective wellbeing.
Denmark came top, followed closely by Switzerland and Austria. The UK ranked 41st. Zimbabwe and Burundi came bottom.
A nation's level of happiness was most closely associated with health levels.
Prosperity and education were the next strongest determinants of national happiness.