After a satisfying lunch, Mr. Qian Bingkun and his wife watched a waitress load their leftover stir-fried tofu and dessert into bags, while their daughter paid for the meal. Busily wrapping the uncooked food in a microwave box of typical Chinese blue-and-white porcelain, the waitress answered that it’s to allow customers to take leftovers after they’ve eaten. Some of the …