Hah, you work in a store? This was cool and very creative, I totally sympathize. I like the entire purpose for the poem, it made me smile.
It might be cool like in italics or parenthasis add lyrics from the song or random lines to add interest (you know, lines that you might hear while working at a store)
"Do you have this in a size three?"

--exoh of the Review Marathon (link in my profile)

I love this! I work at in retail, so I can totally relate. Sometimes, I too, wonder if I'm losing my mind... Especially if I begin to remember in order the songs that are played in the store...

Lol. I think rhyme would make it sound better, but it's very funny anyway.