(I think my previous comment was eaten by /.'s tubes. If this ends up being a re-post, I apologize, feel free to mod it to oblivion)
I lived in Costa Rica for a couple years, most recently about eight months ago. They have a phrase, "pura vida" which could maybe be translated as "the good life", but it's used as a greeting and farewell phrase as well. It's also used as an answer to, "How are you doing?" On the one hand, it seems remarkable that they would be happier than anyone else; broadly speaking I expect people to have the same general experiences anywhere. On the other hand, I spent a few months in Panama and then returned to CR for a holiday, and when I picked up a pizza that I had ordered, the guy said "Have a nice day," that is, "pura vida". And he meant it sincerely. At that moment, the difference in attitude was shocking; I had been used to Panamanians (although I prefer the sobriquet Panamaniacs :P) basically looking at me as a business opportunity at best.
The average Costa Rican does not have a computer, although cell phones are relatively common. Computers are quite expensive, enough to make an import business profitable, but very few people can afford one. There is a 100% import duty on cars, so those are expensive too. They also do a license plate restriction on driving, at least in San Jose. Most have electricity and relatively clean water, although they do have an issue with dumping raw sewage into almost all of the rivers. I wish I could more effectively describe the impoverished living conditions; if you have any specific questions please feel free to ask.
On the other hand, people sure don't care about working hard there. My friends in San Jose tell me that the weekend starts on Thursday, and everyone including the boss is late on Fridays and Mondays. There were as I recall a couple clubs where you paid a $10 cover and drinks were free. If there was paperwork that needed to be processed by the government, let's just say the Vogons would be proud of the Tico bureaucracy. If you needed to have your car repaired by a certain date, the Ticos will of course be delighted to tell you that it will be ready then, but no amount of inducement or cajoling will actually make it ready by a given date. Things happen when they happen, and no one is in a hurry to get anything done or to go anywhere â" they call it operating on "Tico time".
However, all that said, I'm a little skeptical of the article. Most of Costa Rica is really rural, and I would be surprised if the national power grid actually extended to all corners of the country. I don't think that the average Tico really cares about environmentalism; to some degree it's a first world problem. The Costa Rican government on the other hand knows that the country basically has no industries; the farming isn't great and I believe tourism is the biggest part of the economy. Costa Rica doesn't have all that much to tour, either: there are no mayan or aztec ruins, and almost nothing in the way of indigenous culture. I heard something about painted oxcarts being a thing, but never saw one. Contrast with Panama's amazing diablo rojos (the buses or the costumes [staticflickr.com]). So some while back they hit upon the idea to market themselves as a destination for "eco-tourism", which involves convincing the rest of the world that they have some sort of unique level of biodiversity. It may even be true. However, they really need to promote the image of being green and eco-friendly regardless of the truth.
If I could make a decent living there it'd be hard not to go back, even though the world is full of things I have never seen before. Whether or not the Ticos are the happiest people, I think that I can safely say that happiness for me is two-for-one mango daiquiris at the Lazy Mon. Pura Vida!