How does the setting of the story shape Sammy and his reaction?

From the text, we can infer that seeing the girls on the beach wouldn't have had any effect on Sammy at all..... they'd simply be girls on the beach. In the setting of the A & P the girls are a distraction..... alluring.

You know, it's one thing to have a girl in a bathing suit down on the beach, where what with the glare nobody can look at each other much anyway, and another thing in the cool of the A & P, under the fluorescent lights, against all those stacked packages, with her feet paddling along naked over our checkerboard green-and-cream rubber-tile floor.