Few TV shows can attract guest stars of the same caliber as The Simpsons. The names that appear on The Simpsons could rival the names that host Saturday Night Live. The series has been recruiting A-list talent to play one-off characters since its second season when it really became a ratings hit. After three decades on the air, it’s become a milestone in every celebrity’s career to be immortalized in yellow in the curious town of Springfield.

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However, in recent seasons, as the show’s quality has quickly declined, celebrity guest stars have become a crutch to squeeze story material out of a done-to-death premise. As a result, The Simpsons’ guest appearances are a mixed bag.

Best: Kelsey Grammer

Sideshow Bob

Right off the bat, possibly the most memorable guest star in The Simpsons’ history is Kelsey Grammer in the role of Sideshow Bob, Krusty’s disgruntled former sidekick who’s been determined to murder Bart for decades.

There are a few Sideshow Bob episodes, with some great ones and some terrible ones, but arguably the best is season 5’s “Cape Feare,” a spot-on spoof of Scorsese’s Cape Fear remake.

Squandered: Elton John

Elton John in The Simpsons

Apu puts all the other husbands in Springfield to shame when he starts romancing Manjula in “I’m with Cupid,” so Homer and the guys set out to sabotage his love.

When Elton John’s private plane makes an emergency landing in Springfield, Homer and the guys think he’s there to give Manjula a private concert (which he isn’t, but ends up doing anyway), so they kidnap him. John has some funny moments in this episode, but he’s massively underutilized.

Best: Meryl Streep

Jessica Lovejoy in The Simpsons

Meryl Streep is such a terrific actor that even when she’s playing a character on The Simpsons, she disappears into the role. Jessica Lovejoy is so well-rounded in the season 6 episode “Bart’s Girlfriend” that it’s easy to forget she’s played by Streep.

The sign of any great guest role is whether they give the spotlight to the new character played by a famous person to cash in on the celebrity factor or use the new character to develop the Simpsons themselves. In “Bart’s Girlfriend,” Jessica’s not there to show off an impressive guest star; she’s there to create conflict for Bart – and the result is one of his best storylines.

Squandered: Katy Perry

Katy Perry in The Simpsons

When Katy Perry was set to appear on Sesame Street in 2010, she was infamously cut from the episode because her outfit was deemed inappropriate for the show’s young viewers. The Simpsons referenced this in a weird tagged-on live-action scene at the end of season 22’s holiday episode “The Fight Before Christmas,” an episode that already has one gratuitous appearance by Martha Stewart.

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In the scene, Perry appears in a tight dress covered in Simpsons characters and joins Henson-esque puppet versions of the Simpsons in singing some Christmas carols. The cringeworthy sexual innuendos in this scene sound more like they’re from Confessions of a Window Cleaner than The Simpsons.

Best: Dustin Hoffman

Mr Bergstrom in The Simpsons

Lisa began to turn into the outspoken progressive genius that Simpsons fans look up to today when she was inspired by her substitute teacher Mr. Bergstrom in the season 2 episode “Lisa’s Substitute.” Dustin Hoffman brings plenty of both nuance and humor to the role of Mr. Bergstrom, culminating in the emotionally charged “You are Lisa Simpson” moment.

In both the way he’s contrasted with Homer as a father figure for Lisa and the jabs at Hoffman’s career (“Mrs. Krabappel, you’re trying to seduce me...”), Mr. Bergstrom is an unforgettable guest role.

Squandered: Martin Sheen

The real Seymour Skinner in The Simpsons

When Principal Skinner’s voice actor Harry Shearer read the script for “The Principal and the Pauper,” he objected to it. The episode controversially revealed that Skinner is an impostor named Armin Tamzarian who stole a Vietnam veteran’s identity. The writers didn’t expect fans to care, but after nine years of investment in the Skinner character, of course they were up in arms.

The episode features Martin Sheen in the role of the real Seymour Skinner. The star of Apocalypse Now and The West Wing deserved to play a much better Simpsons character than one that shouldn’t have existed and would be instantly retconned.

Best: Glenn Close

Homer and Mona in The Simpsons

Glenn Close first appeared as Homer’s mother Mona in the season 7 episode “Mother Simpson,” one of the show’s most beautiful and heartwarming installments. Its ending, with Homer sitting on his car looking up at the stars, ranks among The Simpsons’ all-time saddest moments.

Although repeat appearances would overdo this conflict, Close’s initial performance as Mona was every bit as emotionally gratifying as diehard fans would expect from Homer meeting his mom. “Mother Simpson” is the anti-“Principal and the Pauper.”

Squandered: Jeremy Irons

Moe's rag in The Simpsons

For definitive evidence that The Simpsons has been scraping the bottom of the barrel for story ideas for the past decade or so, look no further than the season 23 episode “Moe Goes from Rags to Riches,” which chronicles the backstory of Moe’s bar rag.

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A show that used to be about a family before incorporating supporting characters into storylines resorted to an entire episode about a piece of cloth used by one of those supporting characters. Hiring the great Jeremy Irons to play the rag just added insult to injury.

Best: A. Brooks

Brad Goodman giving a seminar in The Simpsons

Albert Brooks has been regularly playing guest characters on The Simpsons since its first season and he’s always been credited as “A. Brooks.” Brooks is to The Simpsons what John Goodman is to SNL.

He’s voiced such legendary one-off roles as Hank Scorpio in "You Only Move Twice" and Brad Goodman. He also played the villainous Russ Cargill in The Simpsons Movie. Without a doubt, Brooks is the show’s all-time best guest star.

Squandered: Lady Gaga

Lady Gaga in The Simpsons

Season 23’s “Lisa Goes Gaga” is one of The Simpsons’ most despised episodes; the writers used Lady Gaga in the laziest way. Whereas golden-age episodes would come up with an inventive reason for a celebrity to come to town, Lady Gaga just arrives in Springfield to teach Lisa the meaning of happiness.

Lady Gaga has more than proven her abilities as an actor. Anyone who can effortlessly play the Super Bowl halftime show and then convincingly portray stage fright in a movie is worth getting a Simpsons guest role they can sink their teeth into.

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