Revealing mistake: Cary Grant shows off his ice skating moves but you can tell it's a stunt double. The double is a bit shorter than Grant. Also in the same sequence, the two other skaters have noticeable doubles as well.
Revealing mistake: As Lulu is pulling her fishing pole out of the school steps, you see if you watch closely that the pole actually passes through the concrete of the steps rather than her lifting it over. (00:02:00)
Revealing mistake: When Joan Crawford shoots van Heflin, he reacts as if he was shot before the shot is fired.
Revealing mistake: When Jerry walks towards the crab with the soda bottle cap stuck on his head, one of the crab's legs disappears for a frame or two.
Revealing mistake: When the businessman rushes back into his bed after closing the window that Daffy opened, he is wearing his normal trousers.