Traditional Seoul restaurants in Jongno-gu still use Korean age counting - you're born at age 1, everyone ages up January 1st regardless of birthday. Makes you 1-2 years older affecting how ajummas address you.

Determines how Gwangjang Market vendors speak to you and social dynamics at traditional Seoul establishments. Most young Koreans use international age casually but older Seoul restaurant workers stick to traditional system.

Don't argue about it at Myeongdong night market stalls, just accept temporary promotion. Creates awkward Seoul moments when you're suddenly same age as someone you thought was younger.