Homer comes across an advertisement in the newspaper for a free trampoline. He rushes to the address from the advertisement, where Krusty the Clown is giving it away, and brings it home. While Bart and Lisa are thrilled by it, Marge is concerned about the potential dangers. However, Homer brushes aside her worries; he has grand plans of turning their backyard into a theme park and decides to charge others a fee to use the trampoline. Inevitably, however, people start getting hurt, and Homer finally takes Marge's advice to get rid of the trampoline. After failing at his various attempts to do so, Bart steps in to help, by chaining the trampoline to a pole using a bike lock and waiting for Snake Jailbird to steal it (who uses it as a bed).
Later that night, Homer admits that while Marge was right that getting the trampoline was a mistake, he's at least willing to go out and try new things while she's boring and just nags all the time. Marge disagrees with this, but then asks Bart and Lisa what they think of her. She discovers that they actually agree with Homer's assessment. Marge becomes angry and offended that people see her that way and goes to hersisters'place (almost hitting Ned Flanders with her car on the way out). While at Patty and Selma's apartment, the twins introduce their younger sister to an informercial featuring self-help guru, Brad Goodman, who can supposedly help people like Marge with their "chronic nagging."
After Marge makes Homer watch a Brad Goodman video with her, she becomes more tolerant and the two start getting along better. After seeing how out of control Bart is, the family goes to see Goodman's live lecture in the hopes that it will change him. Bart interrupts the lecture, but Brad Goodman encourages the town to follow Bart's spontaneous attitude. Soon, the whole town starts acting like Bart, who at first enjoys things, but eventually becomes depressed by it. Lisa explains that it's because he's lost his unique identity as a rebel with everyone else in town acting like him.
The citizens of Springfield hold a "Do What You Feel Festival" where everyone does what they feel. Unfortunately, this results in workers not doing their jobs, culminating in an ungreased Ferris wheel coming off its hinges and crashing into the zoo whereupon the animals escape and run amuck through town. People begin arguing with one another until they all decide to blame Bart. They form a mob to attack him, but Homer rescues him in a parade float. Giving up, the crowd decides to go to the old mill to get some cider.
Back home, the Simpsons discuss what they've learned. Homer feels tha Bart should've been a better role model, but Marge comes to Bart's defense by claiming that self-improvement is best left to people who live in big cities. But Lisa says that self-improvement can be accomplished, but through hard work and not a quick fix, and Homer concludes that everyone's fine the way they are. With that sorted out, the family watches McGarnagle, a show about a cop who solves crimes in his spare time.