In the affluent Seoul neighbourhood of Daechi, Hyun Sung-joo has a dilemma.
His cafe is sometimes visited by Cagongjok, a term for mostly young South Koreans who love to study or work at cafes, but there's a limit.
He says one customer recently set up a workspace in his cafe which included two laptops and a six-port power strip to charge all their devices - for an entire day.
"I ended up blocking off the power outlets," the cafe owner of 15 years tells the BBC.
"With Daechi's high rents, it's difficult to run a cafe if someone occupies a seat all day."
