Yes, I believe that the United States should be higher up in the happiest countries list because we are considered by many as the greatest nation in the world. Although income inequality, racism and gun violence are common problems in the United States, I believe that United States citizens are very lucky because we live in arguably the most free and developed nation in human history.
I personally believe the Human Development Index (HDI) is the best tool to measure happiness and quality of countries to live in. And the Scandinavian countries rightly lead the pack in regards to this. America is by far not the worst country but there is a big gap between them and many other countries.
Firstly the legalized guns. Absurd idea, never lead to a happy life. Secondly the lack of free health care, once again a very unjust stance and does not lead to a happy life. The ridiculously short amount of holiday time they get, leads to unhappiness. And finally the obsession with materialism and superficiality, never going to lead to happiness.
The sheer size of the United States make it very difficult for it to appear on the list of 10 happiest countries. Many of the countries on the list are less populated and do not have overpopulation issues found in many urban areas of the United States. Statistically the overpopulated areas have higher crime rates which leads and this does not bode well for tallying happy people.
The US is not a top 10 happiest country because our economy is not getting better. Today, in the United States, children have it worse than their parents. A lot of people want to be in the work force but they can't find jobs. Until we make the economy better, it'd be wrong to say that America is happy.
The US is a country where people are perpetually unhappy. They always seem to want more and more and complain about they do not have. It is no wonder that with that type of attitude they are not higher on the happiest country list. They have tons of gun violence and obesity, among other problems, that seems like justification for unhappiness.