On our recent trip to Japan we were very confused when paying with credit card.
The cashiers would often ask us a question that we initially could not decipher. Eventually an english speaking cashier explained that they were all asking if we wanted to "pay all at once", or in "installments".
Anyways, I think part of your survival lessons should introduce people to the question that the cashiers are asking, and what the proper response should be to indicate that you are paying all at once -- if that truly is the right answer for western customers!
