people doing their own groceries was a a new 20th century thing. I think A&P and Krogers started the aisle shopping thing, Before that you went up to a counter and told a clerk what you wanted; all the stock was behind the counters.
One of my first jobs was as a sack boy at a Skaggs-Albertson's. It was in an affluent neighborhood, and in those days people tipped the sack boys for carrying the groceries to their cars. The tips usually averaged 3 or 4 times the minimum wage we were getting hourly. WE used to beg for more hours. but hardly anybody ever quit and more hours was hard to get.