Some internet goober (probably from alt.nerd.obsessive) has put together this perfectly cromulent graph which shows all the episodes of The Simpsons ranked by their user-voted IMDB ratings. A few things worth noting here:
1. The show has gone drastically downhill since season 11 which, duh.
2. Clip shows are terrible (but even they are more well-liked than most of the later day episodes).
3. “Homer The Smithers” is a weird choice for the highest-rated episode. (It’s a great episode and all, but still, number one?)
4. One kid seems to LOVE the Speedo man.
5. The Lady Gaga episode was, without a doubt, the Worst. Episode. Ever. with only a 4.9, even beating out “All Singing, All Dancing”. She got more gongs than the breakdancing robot that caught on fire.
Since most sane people stopped watching the show 53 seasons ago, let’s defer to Wikipedia’s description of the episode, entitled "Lisa Goes Gaga":
In the episode, American singer-songwriter Lady Gaga makes a visit to Springfield, where all of its residents are in a state of depression. Main character Lisa Simpson is arguably the most depressed person in the city, prompting Gaga to go out of her way to teach Lisa the meaning of happiness
Yup, and then Lady Gaga announced that she had to go because her planet needed her (Lady Gaga died on the way back to her home planet). So congrats, Lady Gaga, on being the last nail in the coffin on the legacy of The Simpsons. Oh, and also happy 28th birthday.