Favorite role-reversals in media?

I have to go with that iconic Spongebob episode, "Can you spare a dime?"

In it, Squidward loses his job and Spongebob helps him back up by letting him live in his pineapple. Squidward takes great advantage of his hospitality for months, making Spongebob learn he has a breaking point. Usually, it's Spongebob making Squidward angry with his antics, but in this episode, it's the other way around! Hence why it's a role-reversal.