The scene in The Simpsons episode "Cape Feare," where Sideshow Bob continuously steps on rakes, was actually "creative padding" to get the episode to its minimum length.
2. An episode of The Simpsons titled "Lisa The Greek" correctly predicted the outcome of that year's Super Bowl in 1992 just three days later. When the episode was rebroadcast in '93 and '95 it was redubbed and again predicted the winners.
3. Ralph Wiggum was not canonically made to be Chief Wiggum's son until season 4. The two characters were developed independently and only later the writers decided to make them father and son.
4. The Simpsons character "Edna Krabappel" was retired after Emmy Award-winning voice actress Marcia Wallace died in 2013. To acknowledged her death, the chalkboard in the opening sequence was changed to read a single "We'll really miss you, Mrs. K"
5. The Simpsons’ secret formula is written by math geeks. When one of Britain's best-known science writers went to Los Angeles to meet the show’s writers for a new book, he found a team dedicated to inserting gags about complex math problems.
When the band Judas Priest appeared on The Simpsons, they were mistakenly defined as "death metal". The producers decided to apologize for the mistake by having Bart Simpson write "Judas Priest is not 'Death Metal'" in the opening sequence chalkboard gag.
7. Marge Simpson's hairstyle was originally designed to hide rabbit ears for an eventual reveal that she was secretly a rabbit from Matt Groening's comic strip "Life in Hell."
8. Krusty the Clown was originally Homer Simpson in disguise, with the joke being that Bart hated Homer but loved Krusty. Matt Groening later discarded the idea as being too complicated.
9. While recording the original Simpsons "Treehouse of Horror", James Earl Jones chewed on a cookie close to his microphone in order to get the alien drooling sounds just right for Alien Chief Serak.
10. In the Trash of the Titans episode, Homer Simpson's idea to fill a mine with other cities' garbage dissuaded a small Canadian town with the exact same idea.
Maude Flanders (from The Simpsons) was killed in the Season 11 episode titled, "Alone again, Natura-Diddily". The reason she was killed off was due to a dispute between Fox and Maggie Roswell (the voice of Maude Flanders) about a pay rise. Fox refused, and Maggie quit, so Maude was killed off.
12. The Couch Gag in The Simpsons intro developed into a clever way to adjust the show's runtime as needed.
13. The inspiration for the episode "Bart Sells His Soul" came from an experience Greg Daniels had in high school when he convinced a bully to sell him his soul and scared him into buying it back. He did it again until he realized the only person who ever profited on souls was Satan.
14. All characters in The Simpsons have four fingers except for God who has five fingers.
15. Upon first seeing The Simpsons character Hans Moleman, show creator Matt Groening claimed he was so shriveled and unrealistic that he resembled a "mole man". According to Groening, many viewers were offended by Moleman's look. He was made a recurring character in order to annoy these people.
Moe from The Simpsons was only given the surname Szyslak so that he would have the initials M.S., and hence be a suspect in the Burns shooting.
17. In the first Simpsons Treehouse of Horror, Marge warns parents of the content of the episode advising them to put their children to bed. The warning was put in as a sincere effort to warn young viewers, as the producers felt it was somewhat scary.
18. The Simpsons are yellow because Matt Groening thought it would be a perfect way to catch the attention of people flicking through their channels looking for something to watch.
19. The Simpsons released an album in 1990 and the lead single "Do the Bartman" was a worldwide hit. It was co-produced by Michael Jackson, who also provided background vocals and was a huge fan of the show. Following his death, FOX played the video before an episode as a tribute to Michael.
20. In two episodes of the first season of The Simpsons, Lou the cop was colored yellow. It wasn’t till Season 2 that they kept him black.
21Milhouse Van Houten
Milhouse Van Houten is allergic to honey, wheat, dairy, non-dairy, mistletoe, holly, the red part of candy canes, and to his own tears.
22. The Simpsons episode “22 Short Films About Springfield” was a backdoor pilot for a proposed series. 'Tales from Springfield' would have told three different short stories per week, focusing on secondary characters and telling stories about the Simpsons family members’ past or future.
23. Mr. Burns' telephone greeting in The Simpsons, 'Ah-Hoy!' was actually how Alexander Graham Bell thought people should answer the telephone when he invented it.
24. Simpsons characters Lenny Leonard and Carl Carlson both possess master's degrees in nuclear physics.
25. Homer Simpson’s conversations with his own brain were often introduced because it filled time and was easy for animators to work on. Homer's conversations with his brain were used several times during the 4th season, but were later phased out after producers “used every possible permutation.”