It's 10:00 in a Tokyo 7-Eleven, and I am standing shoulder to shoulder with a dozen tourists, all clutching baskets loaded with the same things: fluffy egg mayo sandwiches, katsu curry buns, matcha Kit Kats and warm cans of Boss coffee pulled from heated shelves. Behind me, someone photographs their haul before they've even reached the till. Every few seconds, the familiar convenience-store chime announces another arrival. Nobody is here because they have run out of toothpaste. We are all, quite openly, shopping for the experience.