I live in Korea and it is unreal in the entire Seoul region. As in, when I go to London, it feels empty in comparison. Even Oxford Street at Christmas didn't feel crowded at all.
It took us near three hours the other day to drive the 20 odd miles to the centre of Seoul. That's just a usual day in rush hour. (Normally we'd take public transport but we had the dog and you can't take them on.)
There are certain subway lines that they literally shove you onto in the morning, I mean an employee is there cramming people on physically. One such line, line 9, is designed to take 200,000 passengers a day, but actual takes 600,000. It's fucking madness.
The problem is the same as the UK. Everything is too centralised. In a country of 55 million, 20 million live in Seoul or Gyeonggi-do, the area surrounding Seoul (like Greater London).
On the other hand, hospital appointments are not as issue here (tons of hospitals) and the birth rate is so low that schools aren't an issue either (in my husband's generation, 50 or 60 to a class was normal- now it's 15 or 20). Things like museums, art galleries, popular restaurants, newly opened malls...if you're going during the weekend, just forget it because you're not going to be able to move or get in. People will queue for two hours for certain restaurants.
Countryside towns are dying on their arses though, everyone just keeps moving to Seoul.