Do you know there is evidence of liquid water on Mars? Of course you do. We all know this because some really smart people drinking Caramel Brulée Lattes in a room on earth invented a machine with a big camera on it. That machine flew, all by itself, all the way to Mars. When it got there it took, all by itself, insanely clear pictures of the surface of Mars so the people in the room could say, “Holy cow, it looks as if there is evidence of liquid water up there.” By this time the people were on their 347th Caramel Brulée Latte because it took an unimaginable amount of time for this machine to get there, take the pictures and send them back. But it did it. All by itself. You get my point? I knew you would. 
So, do we want to be behind those people on the regular checkout lines? All we just bought was a rotisserie chicken to round out tonight’s dinner of rotisserie chicken. The people on the regular checkout lines last went shopping during the Pleistocene age and have run out of everything it is possible to run out of, including some things that haven’t been invented yet. No, we want to be over here on the self-checkout line, but there are some tricks to using these self checkout machines. To scan an item you should, apparently, climb up on top of the scanner, then reach down like an ape and swing the item across the glass plate. Or maybe you should lie on the ground and sneak the item up over the glass, or maybe … all I know is that if you are silly enough to just stand in front of the scanner and pass items across the glass a saccharine female voice will say “Please rescan your item,” enough times that you will begin stabbing yourself in the neck with a ballpoint pen.
Another tip has to do with your bags. Yes, it is environmentally sound to bring your own bags, and the area to the right of the scanner is called “the bagging area,” but do not, under any circumstances, place your bag in the bagging area. If you do, a saccharine female voice will say, “Unexpected item in bagging area” enough times that you will begin stabbing yourself in the neck with a ballpoint pen.
On occasion, you will actually succeed in scanning an item. You must immediately set that item in the bagging area. It doesn’t matter if it’s the only item you bought or that you can comfortably hold it in your hand. Just set the little sucker in the bagging area. If you do not, a saccharine female voice will say “Place item in bagging area,” often enough that …well, you know.
If it’s a light item, like a greeting card, set it down with enough ooomph that the bagging area can tell it’s there, but not too much ooomph. If the weight of the item does not seem to match the expected weight of the item you just scanned the saccharine female voice will again say, “Unexpected item in bagging area.” It will say this often enough that when you are finally done your husband, instead of signing his name on the signature pad, will scrawl “F*** You,” on the signature pad. By then he will not care that this missive is going to the credit card company, not the store, and that the credit card company will be saying “What’s this guy’s problem?”
So, in summary, do we want them to take these self-checkout machines away? Of course not. What we want is for them to work. All by themselves.