Continuity mistake: Alan is sitting at the kitchen table talking to his son Jake about a math test that Jake got a bad grade on. At the beginning of the scene Alan holds the open test in his left hand. When the camera switches back to him a second later the test is now in his right hand. Finally at the end of the scene the test is back in his left hand but is now folded.
Continuity mistake: When Alan and Charlie are watching Judith take off her clothes on the monitor screen, Alan takes the newspaper he has in his right hand and puts it in his left hand to turn the monitor off. The next shot shows Charlie walking into the kitchen and Alan looks at him but now the paper is back in his right hand.
Continuity mistake: When Charlie and Berta are in the kitchen talking, Charlie sits down and places his coffee mug on the left side of his plate. A few shots later he is seen placing it again except this time on the right side of the plate. Then just as Berta exits the kitchen, Charlie's mug has now switched sides again, being on the left side of the plate.