There's actually surprisingly little overtime claimed in Korea for all the >40 hour weeks being worked. The simple answer is that Korea (and Japan) have a cult

There's actually surprisingly little overtime claimed in Korea for all the >40 hour weeks being worked. The simple answer is that Korea (and Japan) have a cultural norm where showing dedication to your job/company by working long hours is vastly more important for career advancement (or even continued employment!) than the actual work you get done.