This is definitely something frustrating about Korea, how some people will just leave trash for others to pick up. You even see this while hiking where people will have a picnic and leave trash lying around. With that said, overall the leaving of trash lying around has gotten better over the 20+ years in Korea:

Mounds of trash revisited this year’s cherry blossom festivals nationwide as the streets were strewn with trash, such as disposable cups, delivery food containers and drink cans.
Near Gongji Stream in Chuncheon, Gangwon Province, the situation was particularly dire. As the stream became a famous tourist attraction for enjoying cherry blossoms, garbage was haphazardly disposed of at the recycling center. Cigarette butts also littered the park as if smokers had a vendetta against the lawn.
Similarly, Yeouido Hangang Park in western Seoul faces a deluge of trash every year around festival time.
Despite having over six dumpsters set up, the volume of trash overwhelms the capacity. Overflowing trash cans are a common sight, with waste often found stacked up near trash cans.
Korea Times
You can read more at the link.








