Animation is a long and detailed process, but sometimes mistakes can be made, even in a show as popular as The Simpsons. The animated series first debuted on Fox back in 1989 and almost instantaneously became a hit for the network. Creator Matt Groening managed to deliver a comedic show that was usually appropriate for families, but still managed to push the boundaries.

In the 30 years since the initial launch, The Simpsons has remained a cornerstone of pop culture and continues to be one of the more popular animated shows on television. The large fan base it has acquired was enough for Fox to already renew The Simpsons for two more seasons, ensuring that the show will live on after the Disney-Fox deal closed. Even with all of the acclaim, great characters, and memorable episodes though, even The Simpsons managed to make a mistake from time to time.

Related: 25 Simpsons Deleted Scenes That Went Too Far

Screen Rant's newest video dedicated to The Simpsons takes a closer look at the production process on an animated show and proves just how difficult it can be. With many different teams of animators working on the same episodes, sometimes it's easy for small details to get lost. So, we compiled a list of 20 examples of these moments where a continuity error was not caught until after the episode has aired. Check out the full list in the video featured at the top of this post.

Considering how many different aspects to each individual scene animators have to get right, it is no wonder that some of these details got mixed up. These mistakes can be as simple as changing the appearance of a character in the middle of a scene or even the logo of a particular beverage. They are largely common in quick cutaway scenes though, so these can often be "blink and you'll miss it" errors, which is likely why they weren't caught ahead of time.

That said, it's still somewhat amazing that some of these mistakes were never noticed with several pairs of eyes looking over an episode before it airs. One of the strangest instances that made this list is a woman's nose disappearing as she leaned forward in a shot and then magically reappeared once she leaned back. However, other surprising slip ups come from rather major pieces of The Simpsons, such as the design of their home. As The Simpsons continues to make new episodes, hopefully there won't be too many (if any) instances like these in the future.

More: 15 Animated Show Episodes That Were Pulled From TV