The Harry Potter films (and books) in general.
In modern day society, there is a problem with obesity because of advanced technology replacing the requirement of manual labour, physical exertion, etc. We don't need to walk to get to anywhere; we use the car, train, bus, what have you. We don't wash the dishes by hand, we use the dishwasher. You get the point. We're getting fatter and lazier as as culture because of this.
So, in the "Wizarding world" in Harry Potter, how come the minority of characters have weight problems when the physical exertion of our "muggle" technology is significantly reduced by the flick of a wand? Surely they would have greater problems with an unfit society? Okay, so in our world we take the train. But at least there is some walking involved. In the Wizarding world, all you do is mutter an incantation and you're at your destination!
I want my portly Ron, dammit!
I couldn't get my head around the use of magic, so I'm not even going to bother going there.