This is an interesting query because Sammy is very much a part of the supermarket society in question; however, he does not consider himself a part of it. Sammy very much has an "us versus them" mentality about his presence in the supermarket. He thinks that he is better than the customers, as well as his boss. Sammy repeatedly characterizes the standard shoppers as dumb beasts. The second paragraph already shows this attitude through Sammy saying that he had to smooth over the customer's feathers; she walks away with a snort. The "feathers" comment paints the customer like an annoying bird, and the "snort" likens her to a wallowing pig. Sammy's view of his customers degenerates from there, and readers see him repeatedly refer to the shoppers as sheep, which are a stereotypically dumb animal. The "sheep" are then unable to figure out how to act, where to go, and how to behave once Queenie and her friends show up in their eye-catching attire.

All this while, the customers had been showing up with their carts but, you know, sheep, seeing a scene, they had all bunched up on Stokesie.

The supermarket society is essentially comprised of beastly people, living lives that are so monotonous and boring that three girls in bathing suits can disrupt the entire flow and rhythm of a standard shopping trip.

Sammy sees his typical A&P supermarket society as made up of everyday town locals, especially women, who live uninteresting, unglamorous lives. As he puts it:

these are usually women with six children and varicose veins mapping their legs

Sammy understands the shoppers as primarily working-class people like his family. He draws a contrast between them and the summer vacationers who come to the Point, which is five miles away on the beach. When Queenie and her girlfriends come into the store, they represent to him all the glamour and money of the Point that a typical A&P shopper does not exude. Sammy describes, for example, Queenie's voice as "tony," and it causes him to imagine that:

I slid right down her voice into her living room. Her father and the other men were standing around in ice cream coats and bow ties and the women were in sandals picking up herring snacks on toothpicks off a big plate and they were all holding drinks the color of water with olives and sprigs of mint in them ...

Sammy is so impressed with these girls and so upset when his manager comments on their inappropriate attire that he quits, even though his family needs the money. Through Sammy, Updike makes the comment that supermarket society is down-to-earth, rule-based, and the working class. Sammy aspires to more—whether he is living in fantasyland or not is left an open question.

While he works at the A&P (the largest chain of grocery stores from 1915 through 1975), Sammy perceives the customers as "houseslaves in pin curls" with varicose veins that "map" their legs. He also sees them as "sheep" distractedly pushing their shopping carts down the aisles.

These women are dehumanized because of their repetitive and mindless routines. In fact, Sammy imagines them as animals. Two customers, for example, are likened by Sammy to frightened pigs in a slaughter chute as they vie for first place in the checkout line. So, when the young girls enter the store in their swimsuits, Sammy perceives them as a refreshing change from the usual customers. To Sammy, these girls are independent and vibrant.

When the manager of the store and Sammy's boss, Mr. Lengel, accosts the three girls in their swimsuits, telling them that they must leave the store because they are in improper attire, Sammy envisions Mr. Lengel as a representative of "The Establishment." Further, after listening to Lengel lecture the girls about proper attire, Sammy decides to quit in a rejection of the "stuffy" values of the management and as a gallant act in order to impress the girls. Unfortunately for Sammy, his gesture goes unnoticed by these girls, and he stands outside realizing "how hard the world was going to be [for him] hereafter."

I would add that Sammy also longs for that beautiful white body of the "Queen" who walks into the store.  She represents a class to which he doesn't and won't ever belong (even after he quits his job).  She buys the Fancy Herring Snacks while his family drinks "Schlitz in tall glasses with "They'll do it every time" cartoons stencilled on." But she also can break the rules with a certain audacity, and just as Sammy admires her confrontation with the "sheep" in the store, so does Updike, I think. He doesn't criticize them so much as, with Sammy, mourn and criticize the fact that such a gap exists, one which Sammy will not cross ove. Perhaps they are a representation of The American Dream (often embodied in American literature through wealthy, beautiful women) that the ordinary guy just cannot obtain.

Well, one is the disparity between the vacationing, monied class to which Queenie and her entourage belong and to the resident, working class to which Sammy is a member.  Sammy longs to not suffer the same stagnant fate of his co-workers and to be accepted by the outsiders.  The supermarkert, therefore, might be seen as a metaphor for those who must stock societies "shelves" and those who enjoy its spoils.