Summarize the information Sammy gives readers about his tastes and background. Why is this exposition vital to the story's development?

Sammy tells us how he interprets what he sees around him. This gives us a unique look at his tastes and background. Sammy is nineteen years old and his hormones are raging. We see a streak of rebellion in him amidst the dreariness of the grocery store. This exposition is vital to understanding his intense adolescent angst and longing for something different.