The Woman in RedGoofs
Flustered after being invited on a date by an unwitting Teddy, Ms. Milner gets up and runs out of the office. In the process, she bumps into the water-cooler, knocking off the bottle. As it hits the floor, we hear the sound of glass breaking. However, the bottle remains intact, and it's made of plastic, meaning it's impossible for it to have made that sound.
In the opening scene, Theodore Pierce is shown on a ledge with his back up against the building. The ledge is reasonably wide, and his feet are clearly at least a couple of feet from the edge. When the camera goes in for a closeup, however, his feet are right at the edge, implying a much narrower ledge. In addition to the above, in the long shot, he is standing in front of the window . . . the seagull lands . . . and cut to the closeup, he is now on the ledge between two windows. There was not enough "real time" for him to move sideways on the ledge.
When Gene Wilder's character is backing into his parking space after standing up Gilda Radner's character, he appears to be looking into a rear view mirror in the car but when Gilda's character approaches to damage his car, there is no rear view mirror in the car. There was a rear view mirror in the previous scene involving the car, as well as the next scene involving the car. Also, later in the film the rear view mirror disappears once more when Teddy is driving with Buddy.