Never had a problem at the WalMart near me in southern NH. The cashiers are always cheerful, and the store is always stocked and clean. Even had a dept. mgr call me when an item I was looking for came in!
The service is much worse in department stores such as Macy’s.
One place where they are really going out of their way to treat the customer right is Chick-Fil-A. Maybe they’ve always done this, but they really seem to be going above and beyond at a new store that has opened up locally. They all tell you “My pleasure.” Employees will come to your table and ask you if you need anything. I really enjoy going there when we have even if it is a tad pricey.