Hanoians don’t like plastic. At least not when it comes to money. In Hanoi, you don’t pay by card. You pay cash. As often as possible.
This obviously applies to food (many restaurants don’t even have a card machine, and if they do, then it is often mysteriously broken), but it also applies to the purchase of a refrigerator. Or the purchase of stocks and bonds. Or cars. A friend always carried a suspiciously large handbag with them, and when asked about it one day casually answered: "Oh, that's the money for today’s stock purchases. I'm on my way to the bank.".