Gallup Inc. conducted the survey of 150,000 people in 148 countries and found that seven of the world's 10 countries with the most upbeat attitudes are in Latin America.
The research-based consulting company asked about 1,000 people in each of 148 countries if they were well-rested, felt respected, smiled or laughed a lot, learned, did something interesting or felt feelings of enjoyment the day before.
Panama and Paraguay ranked the highest with 85 percent of people reporting a positive outlook.
El Salvador, Venezuela, Trinidad and Tobago, Thailand and Guatemala, the Phillipines, Ecuador, and Costa Rica followed closely.
Guatemala was ranked the seventh happiest country in the world. The findings were suprising given the region has one of the highest homicide rates in the world.
"In Guatemala, it's a culture of friendly people who are always smiling," said Luz Castillo, a 30-year-old surfing instructor. "Despite all the problems that we're facing, we're surrounded by natural beauty that lets us get away from it all."
Singapore was named the least happy, which comes as a surprise as it ranks among the most developed countries in the world.
"We work like dogs and get paid peanuts. There's hardly any time for holidays or just to relax in general because you're always thinking ahead: when the next deadline or meeting is. There is hardly a fair sense of work-life balance here," Richard Low, a 33-year-old businessman in the prosperous Asian metropolis said.
According to the poll, Armenia, Iraq, Afghanistan, and Haiti were also among the least likely worldwide to report feeling positive emotions.
"Feeling unhappy is part of the national mentality here," said Agaron Adibekian, a sociologist in the Armenian capital, Yerevan. "Armenians like being mournful; there have been so many upheavals in the nation's history. The Americans keep their smiles on and avoid sharing their problems with others. And the Armenians feel ashamed about being successful."
The United States ranked No. 33 in positive outlook.
The study further deepens the correlation between money and happiness. According to the poll, Latin Americans believe the real value of happiness is in intangible unmaterialistic things like relationships, friends, family, and spirituality.
Carlos Martinez of Panama said although he was unhappy with rising crime in the Carribbean country, he found happiness in his family.
"Overall, I'm happy because this is a country with many natural resources, a country that plays an important role in the world," he said. "We're Caribbean people, we're people who like to celebrate, to eat well and live as well as we can. There are a lot of possibilities here, you just have to sacrifice a little more."
Despite agonizing life trials, Panamanian street vendor Maria Solis said she found no point in complaining or mourning over feelings of despair.
"Life is short and there are no reasons to be sad because even if we were rich, there would still be problems," she said while selling herbs used for making tea. "We have to laugh at ourselves."
To see the full list, visit gallup.com
The Associated Press contributed to this report.