What are the conflicts in the story "A & P" by John Updike?

There are three main conflicts in John Updike's "A & P": Man vs. Society, Man vs. Man, and Man vs. Self.

• Man vs. Society

As Sammy, who narrates, checks out an older woman's groceries, he notices three girls who enter the store wearing "nothing but bathing suits." Because he becomes so distracted by these scantily-clad girls, Sammy rings up a box of HiHo crackers twice and the "witch about fifty with rouge on her cheekbones and no eyebrows" is able to catch him making an error. She complains to Sammy.
Further in the narrative, Sammy is critical of some of the customers, calling them names, such as "houseslaves in curlers." Then, he begins to feel defensive of the girls.

• Man vs. Man 

Sammy comes into conflict with the store manager, Mr. Lengel, because he wants to defend the three girls that Lengel has accosted and told, "We want you decently dressed when you come in here." Lengel adds that they must have their shoulders covered, as it is "policy." 
All the time that Lengel talks with the girls, Sammy watches them until he becomes infatuated enough--"scrunchy inside"--to feel that he must defend them. He tells Mr. Lengel that he did not have to embarrass the girls, and in an act of bravado, he quits.

"Sammy, you don't want to do this to your Mom and Dad," he [Lengel] tells me. It's true, I don't. But it seems to me that once you begin a gesture it's fatal not to go through with it....

"You'll feel this for the rest of your life," Lengel says, and I know it's true.

• Man vs. Self

Having acted against his better judgment, Sammy narrates that he keeps thinking of how Lengel made the pretty girl blush. After he has quit, Sammy searches for the girls, but they are gone. He looks through the window of the store, and realizes that he has defended the girls of his generation against the older generation only to find himself in some kind of limbo between the two. For, he does not know if he has acted as a fool or as a hero. Nevertheless, Sammy knows life will be harder: "I felt how hard the world was going to be to me hereafter."