Thomson ReutersThe world's unhappiest country is not war ravaged Syria, nor is it Afghanistan, which is locked in an escalating battle with a resurgent Taliban. Instead, the world's unhappiest nation is the tiny landlocked nation of Burundi in sub-Saharan Africa. Although home to only 10.3 million people, the nation was judged to have the least happiest people by the fourth annual World Happiness Report by the Sustainable Development Solutions Network.