John Updike's short story "A&P" is about a teenager who has to make a serious decision. The story is set in an A&P supermarket in a town north of Boston, probably about the year 1960. As the plot unfolds, Sammy changes from being a thoughtless and sexist boy to being a young man who can make a decision, even though it might hurt him.

Sammy tells us he is nineteen years old. He is a check-out clerk in the local A&P, where the boss, Lengel, is a friend of Sammy's parents. Sammy does not seem to like his job very much. He calls one of his customers a "witch" and says the other customers are "houseslaves" and "sheep." He himself comes from a middle-class family. When they have a party, he says, they serve "lemonade and if it's a real racy affair Schlitz in tall glasses with 'They'll Do It Every Time' cartoons stencilled on" (15). In addition, Sammy is sexist. He gives long, loving descriptions of the girls who cause all the trouble, and he thinks at first that girls may not even have minds, asking, "do you really think it's a mind in there or just a little buzz like a bee in a glass jar?" (13) However, he does change as the plot goes on.

The plot of the story deals with three girls who come into the store dressed only in bathing suits. They make their entrance in the very first sentence, and they complicate Sammy's life. At first, Sammy, his older friend Stokesie, and McMahon the butcher all look at the girls lustfully. But of them all, only Sammy enjoys the entertainment the girls bring. The other shoppers crash their carts, look stunned, and are suddenly jarred out of their everyday routine. Sammy, who seems bored with his job, finds the change amusing. He even begins to feel sorry for the girls when everyone else stares at them lustfully. The plot's major conflict occurs late in the story when Lengel, the manager, comes in and scolds the girls. Sammy knows that they are on their way out of the store, but Lengel has to yell at them and make them feel bad. In retaliation, Sammy quits and walks out of the store, hoping to be a hero to the girls. However, the girls have gone, and Sammy is left alone to realize that his life will be a hard one if he always stands up for underdogs.

Sammy's character does change in the story. At first, he is bored and dull, no better than one of the "sheep" he makes fun of. Later, as he watches McMahon, the butcher, "Patting his mouth and looking after them, sizing up their joints" (14), Sammy begins to sympathize with the girls. Then when Lengel scolds the girls and falsely tells them that it's store policy that they have to have their shoulders covered, Sammy realizes, "That's policy for you. Policy is what the kingpins want. What the others want is juvenile delinquency" (15). He now identifies with the girls; he is one of the "others" who disagree with the kingpins. When Sammy makes his decision to quit, Lengel pretends not to understand him, forcing Sammy to reconsider. Sammy still decides to quit. He knows his grandmother would be proud of him for standing up for the girls. However, he does admit that trying to stand up for everyone who is mistreated will make his life hard from now on.

In "A&P," Sammy begins to mature. He is not yet fully an adult, but he has taken a step. Adult life means having to make decisions everyday, and then having to live with those decisions. This is the lesson Sammy has begun to learn in John Updike's story.