Best comedy TV mistakes of all time
Continuity mistake: When Rachel finds out that Ross and Julie are getting a cat, watch Rachel's neck. When she says "together?" she's not wearing a necklace; cut to Ross and Julie for a fraction of a second, then when it cuts back to Rachel saying "both of you?" she's suddenly wearing a necklace. It then disappears again when she says "isn't that just lovely?" hanging off the side of the tray she's holding.
Continuity mistake: In this episode Pam and Jim are talking about how Jim used to have a crush on Pam when she first started here. This implies that Jim was working here when Pam was hired. However, in 4-3: Launch Party Pam says that when Jim first started working there she said, "Enjoy this moment, because you're never going to back to this time before you met your desk-mate, Dwight." These two scenes contradict each other.
Continuity mistake: Lily and Marshall mention that they've been using the same toothbrush ever since they've been together, but in the 14th episode of the 1st season, "Zip, zip, zip", Marshall and Lily are simultaneously brushing their teeth with a tooth brush each (before Ted and Victoria get home).
Character mistake: Season 3, episode 12, "Mr. Monk Gets Cabin Fever": When Randy Disher is having Chinese food in his apartment with his new girlfriend, he gets a fortune stating that he is going to get money from his uncle. Randy says that he doesn't have an uncle. In Season 5, episode 14, "Mr. Monk Visits a Farm", Randy inherits a farm from his uncle who appears to have committed suicide, but was actually murdered.
Visible crew/equipment: When Dewey yells for Lois because the bow was put on the present, if you look to the left of Lois, you will see a crewmember kneeling down, handing Lois the red dress, who is holding a bucket of water. He quickly gets out of the camera's view. [This is on the DVD of the first season. Someone said on the audio commentary that after catching it, they deliberately left it in to see if anyone would spot it. It's still a mistake, but that's why it's there.]
Continuity mistake: In episode 10 (Joey's Place) the Tanner family move Joey into the garage, redecorating it so the entire place is filled with Joey's furniture, but in episode 12 (Our Very First Promo), it shows the characters in and out of the garage which is completely empty and back the way it was before Joey moved in. Later in the episode Joey's stuff is out of the alcove again.
Continuity mistake: When Howard is almost done moving out of his mother's house, there is a table in front of him with a measuring device in the top corner. In one shot, the device moves to the opposite corner of the table. In a few shots later, the item returns to its original position.
Factual error: Kryten tells everyone that the matter paddle transmits matter in digital form from one place to another at the speed of light - he is very clear on this point. He then locates Waxworld, which is 200,000 light years away. Okay - so when they use the matter paddle to transmit themselves to Waxworld, why doesn't it take them 200,000 years to get there?
Continuity mistake: This is a mistake for the introduction for the later episodes. When Homer screams, he turns round. You see this in a wide shot. There are no boxes to the right of the door in the garage. However, two just appear out of thin air when he runs through the garage.