During my twenty-three-year absence from the U.S., a new way of doing business popped up. It became possible for people to do something which I never imagined that they'd allow them to do. That is, they could check themselves out at the register. In fact, there are some places which only do self-check-out ("Fresh & Easy"). At first, I found the prospect intimidating. Now, I wish every store had that option.
The reason that I love self-checking out is that it means I don't have to wait behind some granny or grampy who doesn't seem to understand the fact that money will have to exchange hands at the end of the transaction. The idea that the logical conclusion of events should also be preceded by the removing of ones wallet from a bag or pocket also seemed to come as a shock to many customers in Japan as they only reached for their cash when the checker had his or her hand (or cash tray) out and asked for it.
There are still slow payers in the U.S., but the use of debit and credit cards as well as self-check-out makes it less frequent and offers a way to get around such people. I certainly don't miss the slow paying people who seemed to always be in line in front of me in Tokyo.