That is why I hate Walmart. I shop for the groceries more often than my wife because she works out of the home.
I refuse to go to Walmart because that has happened to me more than once. They will have 36 checkout lanes and only 8 staffed with one person. Typically there are 3-4 people waiting in each line. Also, Walmart is more expensive than my local grocery store chain Market Basket.
I have the same issue with Home Depot. Although there I am usually only buying a few items and I go to the self checkout. They tyically will only have one or two checkouts with an actual person.
I HATE self checkouts and REFUSE to use them. Everytime I try, something errors and I have to wait on the clerk to fix. Usually a weight thing or odd sized item (of which there are many in a hardware store).