Though the weather, beaches, and culture make them seem attractive, they're all rotten inside: Venezuela, Argentina, Jamaica, Spain, Brazil, and Greece now rank among the world's most miserable countries according to a recent study by The Cato Institute.

Using data from the Economist Intelligence Unit, Professor Steve Hanke of Johns Hopkins University calculated every country's "misery index score" based on a mix of unemployment, inflation rates, and its percent change in GDP per capita. Aside from raw numbers, though, each nation was assigned a major contributing factor, or MCF, to explain why it's so glum.

Venezuela, for example, landed itself at the top (or rather, the bottom) with a score of 79.7 because of terrible inflation. Iran came in second, scoring 61.6, also due to inflation. And because it's still Iran.

The study found the least gloomy country to be Japan, with a score of 5.41, with unemployment being the biggest problem. Still, it's not surprising Japan's the happiest of the bunch, given the imminent opening of its Harry Potter world and the fact that snowball fights are an actual sport there.

As for the United States -- where retail workers are required to wish you a nice day -- the richest country in the world ranked in at No. 71 with 11.0 sad points, citing unemployment. Americans can at least take solace in having some really funny cities, so it's not all bad news.

To see some of the most miserable countries on earth, check out the results of the study below, and read the whole thing here: