I was at Singil station, transfering from line number one to line number five. Downstairs on the platform, there's a coffee vending machine where I came to a halt. I fished for some coins but was shy of a hundred Won. I took a thousand-Won note and inserted it in the slot.
The machine read it and indicated with dim, little lights which beverages had become available to me. I pushed the button for milk coffee and heard the paper cup falling into its rightful position. To get the remaining six hundred back I pushed the change-return button and waited.
To my surprise, the machine spit out the same bill I had fed it before. I opened the half-transparent mini door to check on my coffee, and sure enough it was right there. So I took the coffee, took the cash, and walked away. And that's the best thing that happened to me in weeks.