Since it's so easy to walk around in the city, my first choice is always to walk if I can. Plus, I always find cool stores and shops to explore when I walk, and Seoul is filled with cool things to see!
All of these modes of transportation are built for the fast and busy lives of Koreans. They work great and can be used by anyone, anywhere, at almost anytime. They also reflect the value that Koreans have for respect - buses and subways are always very quiet, and people always allow the elderly to have their seats. Whenever you scan your card to pay the bus fare, the machine will say 'thank you'!
I also think that public transportation is very popular because not only is Seoul incredibly huge, but it also has many big hills. I've had to walk up some of these hills, and it is very hard! Buildings that are built on these hills also have small streets and narrow alleyways, which is why delivery drivers often use motorcycles instead of cars, so that they can fit.
