But how do you measure happiness? Perhaps health is the best way because a famous doctor once said, 'Happy people generally don't get sick. 'It's also easy to measure how many people feel ill or unhealthy in a country.For example, one survey says Iceland is the 'healthiest country in the world 'because men and women live a long time there, the air is very clean and there are more doctors available per person than anywhere else in the world.