I had a young adult sci-fi short story collection when I was a kid that included a wonderful story for a budding FA. A mysterious storefront opens up in town that serves the most delicious, calorie-laden desserts imaginable, entirely for free.

Of course, a week later an expensive but effortless weight loss service opens up across the street that burns off about 5 lbs per visit and leaves the customer with a tiny blue tattoo the size of a pinprick on their wrist. The two shops are hinted to be run by the same company, and it becomes a massive success: all the girls at school gorge themselves on these desserts every day and spend all their parents' money at the weight loss place.

The story described these tattoos becoming the height of fashion, with some girls getting them so often it became like a full bracelet around their wrist.

I spent many hours imagining what would happen if the machine backfired and all those pinpricks were reversed. Or thinking about the girl who helped herself to the desserts all day and didn't give a fuuuck about the other shop.