I always use self-checkout and prefer it. Recently though it's gotten really annoying in the Walmart near my house in that there are like 30 checkouts out of which only 4 are working and there's again a line up. Probably again some stupid shoplifting prevention strategy, but it's highly nonsensical.

On a similar note, I'm blown away by the checkout system in Decathlon stores. You literally just throw the item into a checkout bin and it somehow detects what the item is (maybe NFC tags?) And just adds the price on the screen. No weighing or scanning barcodes. Really futuristic!