Do I want my milk in a bag? Why do they ask that? Of course I want my milk in a bag. You put everything else in a bag, why not the milk? Perhaps you're lazy and don't want to bag one more item than you have to. Or you're trying to make it difficult for me to get my milk home. Perhaps next time I will say, "yes, I want my milk in a bag--a paper bag. That would be the most inconvenient way to transport my milk, don't you think?"
And while we're on the subject, what's with this new "Self Check-Out" business? I spend all this money buying groceries, and instead of serving me, you make me scan them myself? It's easy enough to scan the ones with barcodes, but what about bakery items, doughnuts and muffins? I don't know the codes for those. "Please wait for customer assistance, " the computer says. So the lady, from her supercomputer checkout mainframe, has to yell over, "What are those?" "Two doughnuts!" I wait for a few moments until the machine shouts at me, "Please place item in the bag." I guess there is an upside of self check-out: I get to put my milk in a bag myself.