Random Mistakes in '90s Sitcoms That You Never Noticed Until Now (21 items)

(#7) Wedding Ring Mishap On 'Will & Grace'
In the pilot, Ellen and Rob are wearing wedding rings, but their wedding is not announced until season two.
(#12) The Ghosts Play Cards On 'Frasier'
(#13) The Newspaper Switch On 'Seinfeld'
(#6) The Case Of The Materializing/Dematerializing Red Ribbon On 'Seinfeld'
(#1) The Impostor Pretending To Be Jennifer Aniston On 'Friends'

One thing is for sure: you need to go watch season 9, episode 15 of Friends again. If you do, you may notice a decidedly non-Jennifer Aniston actress playing our beloved Rachel Green. One fan noticed the impostor while binge-watching the series on Netflix. In one scene of "The One with the Mugging," Rachel and Joey rush in to Monica's apartment.

At this point, Rachel is still played by Aniston. But during Joey and Monica's back and forth, you may catch a glimpse of a brunette standing exactly where Aniston once was! Magic? Evil doing? A stand in who accidentally made it into the shot? You be the judge.
(#20) The Case Of The Changing Newspaper On 'Family Guy'