Having just done a post on March 2 on an article in the Economist reporting most happiness in poor and middle income countries (most Europeans less happy than rest of world), now appears a "World Happiness Report" (PDF here, Summary by lead author Helliwell here) prepared for a United Nations conference on happiness, that rates developed Northern European countries as having highest happiness. Compare the graphic below with the one in the March 2 post. Helliwell: "the richest countries are a lot happier than the poorest." The Economist: "the highest levels of self-reported happiness is not in rich countries." I guess the way you ask the questions is rather crucial, and also sample size, but at the moment I'm not patient enough to figure out what is going on. Maybe a helpful reader will resolve all in a comment on this post.