The woman at the self-checkout at the grocery store fills up one plastic bag with her avocados and eggs and cans of pink salmon, and then takes the bag and sets it on the floor.
There's a scale under the bags that makes sure that we're not robbing the store blind, and it objects strenuously to the woman's removal of the bag, but she doesn't even notice, nor, when she does notice, does she know why the machine is objecting.
She keeps scanning stuff, which makes the machine squawk a short, garbled, digital curse each time she does, but she doesn't even notice until finally the machine announces, in a delightfully cheerful voice, that she should "Put the scanned items back on the scanner scale."
I make eye contact with the self-checkout monitor who's watching the whole transaction with appropriate boredom, and I shrug, a gesture she considers before giving an elaborate shrug/eyeroll and then going over to the woman who is staring at her self-checkout machine in baffled defeat.