In "A&P" by John Updike, what is the story's central conflict? Does it seem to be a serious or trivial conflict?

"A&P" by John Updike is a coming of age story about a teenager named Sammy. He is a local in a resort town, from a family that is struggling financially--and therefore he works part time as a cashier at A&P, a supermarket that was part of what was, at the time the story was written, the largest supermarket chain in the United States. 

The main conflict in the story is between Sammy and his supervisor...

"A&P" by John Updike is a coming of age story about a teenager named Sammy. He is a local in a resort town, from a family that is struggling financially--and therefore he works part time as a cashier at A&P, a supermarket that was part of what was, at the time the story was written, the largest supermarket chain in the United States. 

The main conflict in the story is between Sammy and his supervisor Lengel. A group of teenage female tourists have entered the supermarket. They are, by local standards, wealthy and scantily clad. The manager tells them, “We want you decently dressed when you come in here.” Sammy defends the girls and makes a grand gesture of quitting.

On one level, Sammy is behaving in a silly manner. His family needs the money, the girls don't notice him, and the issue is a trivial one. On the other hand, this is a key moment in Sammy's own imagination, where he decides to identify himself with the outside world of the tourists and a cosmopolitan society with freer sexual mores rather than his small town. It is a gesture of adolescent rebellion, which is a key stage in the development of a young person into an independent adult. Although the events and gesture are both silly from one point of view, from a broader perspective, they are important to Sammy in creating a sense of his own identity.