Seo Jae-pyoung is used to scrolling through his phone and reading about how South Koreans work too much and under too tight of deadlines. And whenever that happens, he often thinks about the long, onerous days he put in for the North Korean government.

Seo remembers North Korea’s infamous “speed battle” campaigns, which forced poorly-paid citizens to put in grueling hours on state projects for months at a time — and with no overtime payment.