Korean dishes, like superheroes, are traditionally granted special powers. Kam ja tang, a potato and pork-rib stew, is a hangover cure. Chicken feet will improve your complexion — just ask any teenage girl. And grilled eel or chicken soup with rice and ginseng are among the many dishes that servers will earnestly tell you are “good for stamina.” After a five-month stay in Seoul, I’ve decided that the last quality is not simply innuendo but a key survival skill if you live and work in this tireless metropolis, where even dinner can be an eight-hour marathon.