Americans are used to getting whatever they want, whenever they want. Going to the grocery back home store isn’t a battle, one where you push your way through people or have to prepare yourself for getting into a 15 minute argument with the cashier after they tell you that the oranges that were clearly marked on sale aren’t actually on sale.
Literally the same thing happened to me when I moved to India from the developed world. The checkout lines at even the biggest hypermarkets are painfully slow, and annoying. There's no one to bag the products, and they
Don't expect them to have a sense of urgency at the small grocery stores thought. They take their own sweet time checking each and every single product for expiry date, discount or whatever.
It's definitely a culture shock for anyone who's lived in a developed country and is used to lightning fast service.