Swimsuits were basically the most natural attire to wear during summer vacation, and you knew that you didn't want to spend the rest of it in colder clothing, because you would sweat. Some people find other people in swimsuits attractive once they see each other in them, but you were looking for something special.
Before finding what you wanted to buy, you notice a sign labeled "Take off, and leave clothes here" next to the changing room, and below that you see a laundry basket containing clothes some people must've taking off before finding clothes. Just then, you spotted a bunch of people walking naked, while picking out clothing, and blush wondering if the supermarket staff would allow them to do that. You never saw people streak in a supermarket before, so this was the first time for you.