Revealing mistake: At the end, as Ray's parents walk out the back door, Robert says "extra credit". Look out the door when he says this, and you can see the house in the distance wave as if it were a painting.
Revealing mistake: The orange soda cans are supposed to be full but when they fall they are obviously empty.
Revealing mistake: Near the end when Randy is driving away with Harry you can see that the steering wheel doesn't move when Randy turns it.
Not in the Line of Fire - S3-E15
Revealing mistake: Two thirds of the way into the show, Mike and the mayor are talking in his office. If you look at the Mets hat behind Mike, the NY emblem is upside down.
Revealing mistake: It is very easy to tell when Salem is a real cat and when Salem is a robotic cat.
Blue Wants to Play a Song Game - S1-E14
Revealing mistake: After Blue and Steve play the monkeys jumping on the bed game with the sock monkey, when the mail time song plays Steve gets up excitedly and his arm and hand get cut off.
The Aptitude Test / Oskar Gets a Job - S3-E9
Revealing mistake: The test paper Eugene put back in Harold's folder is blank.
Suggested correction: The paper is not blank. Helga used a purple pen to fill in her paper, and Eugene put it in Harold's folder. The paper is filled with purple ink.