Revealing mistake: When Topanga is "naked" under the cover, at one point, you can see a large corner of her bra. (00:02:58)
Grandma Was a Rolling Stone - S1-E7
Revealing mistake: When Eric first meets Mr. Feeny's niece, he throws a bag of mulch. When the mulch lands, you can see the fake grass move, and the fake background swings a little bit.
Cory's Alternative Friends - S1-E4
Revealing mistake: While Cory and Topanga are handcuffed together, trying to convince their classmates to sign a petition to keep Mrs. Rosemeade, Cory is seen mouthing the lines the others are saying while waiting to say his own.
Revealing mistake: The firefighters, apparently the fastest men in the universe, appear no more than 10 seconds after the fire starts.
Revealing mistake: In the epilogue when Eric and Jack's skeletons collapse, the wire holding them up is visible.
Revealing mistake: While the girl who just broke up with her boyfriend is on the phone with the ex, she is throwing his stuff out the window. As she throws the last couple of CDs out the window, you can see the backdrop of the beach sway a little bit.
Revealing mistake: When Cory writes "Hey Dude" on the chalkboard, you can see how it had been written and erased several times, indicating previous takes.
Revealing mistake: When the noir version of Eric is talking about the noir version of Jack as he is playing the piano, you can see Jack is just tapping his fingers against the piano keys and not actually striking them. (00:05:33)
Revealing mistake: When Cory opens up the curtains of his bungalow to show Topanga the beach, you can tell the background is just a backdrop, as there are no waves approaching the shore. (00:10:36)
Revealing mistake: When Eric picks up Cory to show him the "For He's A Jolly Good Fellow" dance, Cory screams that Eric is going to knock over the candles, upon which one of the candles on the desk is knocked over and sets fire to the curtains. If you look closely, neither Eric or Cory bump any of the candles nor the desk they are on, the candle just tips over on its own, suggesting an off-screen crew member used wire or string to pull the candle down. (00:07:18)
No Such Thing as a Sure Thing - S7-E4
Revealing mistake: When the family is eating dinner, throughout the scene you can see Jack dabbing his fork into his mashed potatoes and raising the fork to his mouth with little to no potatoes on it in order to give the illusion that he is eating. (00:03:57 - 00:05:05)
And Then There Was Shawn - S5-E17
Revealing mistake: When Shawn unmasks the killer and it is revealed to be himself, you can see that the body double that does the unmasking has sideburns and extra scruff on the back of his neck, making him noticeably distinct from Shawn. (00:18:17)
Revealing mistake: You can tell the ocean visible from the dorm room window is just a backdrop, as there are no waves approaching the shoreline.
Revealing mistake: When Topanga emerges from the kitchen with more ice for Cory, instead of seeing the kitchen through the open doorway, you can see a wall with framed pictures, suggesting another set was there in place of the kitchen.
The Heart is a Lonely Hunter - S3-E15
Revealing mistake: When the news director is flipping through the booklet that is Arthur's résumé, you can see the pages are blank.
A Kiss is More Than a Kiss - S3-E14
Revealing mistake: When Cory puts the talking teddy bear that Topanga gave him in the trash compactor, the bear screams and Alan and Amy come down to investigate. Amy opens the trash compactor door and pulls out a bear crushed into a cube, but if you look closely, you can see the original bear still in the trash compactor unharmed.
Revealing mistake: During the montage of Eric and Frankie's game of pool, at one point Frankie hits two balls that spin towards a pocket in unison. When both balls come to a stop, you can see a dent in the green ball where a wire or other device would have been inserted to keep the balls linked together.
Revealing mistake: When Amy steps into the living room and sees Reginald, you can see a plain white wall behind the door that leads into the kitchen, when you should be able to see the kitchen itself, which would suggest another set was placed there and they didn't move it for the filming of this scene.
Revealing mistake: When Cory and Shawn are holding band auditions, if you watch the guy that is shredding on guitar, you can see that although he is moving his fingers all over the fret board, his picking hand remains motionless, showing that he isn't actually playing and the sound was added in post production.
Revealing mistake: When Eric tells Cory and Shawn that the hot chocolates were $4, Cory looks up at the prices and says "that's the retail price." As the scene and the rest of the episode go on, if you pay close attention to the sign that has all the prices, hot chocolate is not an item.
