Friends aired in 1994 and is still a common obsession over 20 years later. You might have gone through the show five times now and know all the best quotes and the episode names, but did you ever see "The One Where They Replace Rachel"?
Fans have pointed out that Rachel suddenly changed her shirt, as well as being replaced with Rachel's double. Others have pointed out similar goofs throughout the show, including Monica being replaced in a scene.
In “The One With Rachel’s Date” (Season 8, Episode 5), Monica is talking to Phoebe about her haircut. She is first shown sitting on the couch, facing the camera, but once it cuts to Phoebe, it shows Monica's profile. But it's not Courtney Cox!
These little mistakes probably happen way more than we realize, but of course, it's us crazy Friends fans who would point them out. We wonder how many other scenes have moments like this.