I have this theory...that how much a country sucks is correlated with how many people of that country decide, "Yeah, living in this country is alright, but I'd prefer death."
Just half a century ago, Korea was nothing more than mountains, fisheries and World War II rape victims. In the 400 or so years before that, Korea's only significant role on the stage of history was to be a ripe young boy for the molestive use by China, Japan, and the Manchu. The territory of Korea was mountainous, largely unarable, and contained few natural resources, unless potential rapees count. In the 60 or so years that the People's Republic of Korea has existed, they have developed the southern half of an agricultural society into an economic world power with cutting edge technology in communications, health care services, and travel infrastructure. It is one of the safest nations on the planet as far as violent crimes and theft. On a global scale, their literacy rates, health care, life expectancy, and GDP/capita are excellent. One would expect the citizens of a country that has rose so high so fast to be proud and happy. Well, they're definitely proud, anybody who's ever met a Korean or a Korean-American can tell you that. Ask them if they are happy, they'll probably say yes, though that might be a matter of pride rather than honesty.
South Korea has the second highest suicide rate in the world, with a female suicide rate twice as high as #1 (Lithuania). Of the 30 OECD countries S. Korea is at the top, far higher than Hungary and Japan, number 2 and 3, respectively. The gap is especially pronounced for Korean females, who are more proficient at killing themselves than females in any other part of the world. Suicide is the leading cause of death among people younger than 40 years old. A Korean is more likely to be killed by him/herself than another person or any single disease. That's pretty fucking perverse when you take into account that reported suicides are estimated to be only 10% of total suicide attempts.
I have faith in suicide rates as a proxy measurement for quality of life, moreso than GDP/capita or anything else, so to me it's quite evident that the average Korean does not enjoy a good life here. The discontent starts at a young age. Young, as in like ten. Seriously, can't make shit like this up. This girl is seven years too young to suck her first dick but she orchestrated a premeditated suicide by looking up painless methods on the internet and writing suicide letters to eight of her friends. Do you know how young ten is? That's fourth grade.
Some insight into Korean life might allow you to better speculate why they are so unhappy: