When we're finished roaming the aisles of our supermarket, plucking off the shelves what we need and jamming everything helter-skelter into a plastic basket, we proceed to a checkout lane.
The checkout lady, a bandana around her head, smiles and bows and starts to ring up our purchases. She calls out the price of each item as she rings it up and just to make sure we're on the same wavelength the price appears for us on a digital display.
As she rings things up, she carefully arranges them in another basket: she puts the lemons together in one corner, the can of onion soup next to the can of clam chowder. She puts the quart of green-tea ice cream into a plastic bag of its own and the three ears of corn last so nothing rests on them. This careful, not so say artistic, arrangement seems a gentle reproof to the jumbled pile we gave her. I later ask why such a careful arrangement, which after all does add some seconds to to the checkout process in a busy supermarket, is tolerated. I am told that supermarket customers expect it, that they would raise an eyebrow if it were not done.
This, even though at the end of the transaction we must take our carefully arranged basket to a quiet corner and transfer our purchases to bags of our own that we have brought with us. The supermarket, in an economy measure, does not provide its customers with paper bags. Everybody understands this and now brings their own bags.