"Those who move to happier countries gain, while those who move to less happy countries lose", though the adjustment of happiness is not complete, as migrants still reflect in part the happiness of their birth country.
On the global stage, Finland is now the happiest country to stay in the world, displacing Norway, which topped the index in 2017.
Experts presented the world report on happiness. Denmark was third, followed by Iceland and Switzerland.
The World Happiness Report was released by the Sustainable Development Solutions Network for the United Nations on March 14, days before World Happiness Day on March 20. Tellingly, the report revealed the USA to be in a state of happiness decline, slipping to 18th place, while Australia just managed to scrap into the top 10.
The countries on the report were ranked on six key variables that support well-being: income, freedom, trust, healthy life expectancy, social support and, generosity.
Click through for the top 10 countries, ranked by happiness.
A new report has found the Scandinavian nation is the happiest place on Earth, toppling neighbour Norway from the top spot. The largest groups of immigrants come from other European countries, but there are also communities from Afghanistan, China, Iraq, and Somalia.
"I've joked with the other Americans that we are living the American dream here in Finland", said Brianna Owens, who moved from the United States and is now a teacher in Espoo, Finland's second biggest city with a population of around 280,000.
The 2018 report was released Wednesday, ahead of the United Nations' International Day of Happiness, and it has the United States ranked 18th. It is noted that in Finland live approximately 300,000 visitors and residents with foreign roots out of 5.5 million people.
According to the survey, people in Burundi are unhappiest with their lives, followed by Central African Republic (155), South Sudan (154), Tanzania (153) and Yemen (152).
For the first time since it was started in 2012, the report, which uses a variety of polling organizations, official figures and research methods, ranked the happiness of foreign-born immigrants in 117 countries.