This summer, I worked at a grocery store as a bagger and cashier.
Take your one hour per week of hearing this music and multiply that by 25 to 30. Tack on to that a really annoying supervisor and customers who ask for price checks every other item, and you've got yourself a party!
Actually, my store wasn't nearly that bad. The music was low, all but two of the workers were nice, and the shoppers were fine. But I've heard horror stories from other branches.