Continuity mistake: When Jennifer comes into work the next day after her dinner date with Dick, her face is covered in hives from an allergic reaction. Later when Dick interrupts her choral group, the hives on her face have disappeared. She and Dick are wearing the same clothes in both scenes, so she couldn't have overcome such a reaction in such a short amount of time. (00:12:30 - 00:15:00)
Continuity mistake: In the scene where Dick is buying a laptop, you can see that while the computer is on his lap, it is not really on. (00:06:40)
Continuity mistake: The bottle of orange soda on the breakfast tray Dick tries to bring to Mary changes to a bottle of alcohol (Jack Daniel's I believe) when he sets it down. It later changes back into the bottle of orange soda.
Dick's Big Giant Headache (1) - S4-E23
Continuity mistake: After Harry eats the egg, the lid is still up. When Vicki walks in, the lid is down.
Continuity mistake: When everyone is in the living kitchen, Tommy ends up getting 2 darts stuck into the dartboard. When Harry throws the remote, the 2nd dart is missing. But it's back in the wide shots after Jennifer comes in. Later, when Tommy throws another dart, that 3rd one is seen, but not the 2nd one.
Continuity mistake: Mary's glass of wine goes from being almost empty to about half full during her conversation with Charlotte. In the same scene Charlotte goes to put the bottle down but in the next shot she is still holding it.
Continuity mistake: During a conversation between Sally, Mary and Nina about posing for "Playpen" magazine, Mary's glasses are on one second, and then off the next. This mistake repeats twice in thirty seconds. They're nowhere to be seen otherwise. (00:13:30)
Continuity mistake: In the scene where the F.B.I. storm Dick's house, Charlotte's sleeves change length (i.e. being pulled up or like normal) throughout the entire scene. (00:20:00 - 00:20:30)
Continuity mistake: Dick hands Nina a box full of dishes and asks for them to be cleaned. She then drops the box on the ground where it lands upright. All of the dishes remain in the box. The next time it's seen a few seconds later, it's suddenly on its side with dishes scattered across the floor. None of the characters touch it and there is no sound indicating that it magically tipped over by itself.