Different entities have conducted studies to determine the happiest nation on earth. The results have differed, depending on the criteria and method used. If you refer to the World Database of Happiness, the happiest people on earth can be found in Costa Rica. Denmark comes at a close second. Surprisingly, the United States only ranks 20th. At the other end of the spectrum, we have Togo and Tanzania. The method used in this study was to ask the citizens of the countries to rate their own happiness. There was a total of 148 countries surveyed.