Plot hole: When Elaine is searching for Jean Paul in the streets, one of her verbal flashbacks is of Jean Paul saying, "I trust Elaine, she is my friend." However, Jean Paul made this remark to Jerry, and Elaine was not there to hear it. How could she have a flashback of it?
Other mistake: The tenant board member tells George that Mr. Eldrige in apartment 8C has decided he wants the new apartment. However, the new apartment in question has a 3-digit number - 808 I believe. This indicates that the building would not have single digit numbers and letters (Such as 5E, 8C, etc.) as part of its numbering system.
Add timeBrittle Fingers
Continuity mistake: In the episode "The Suicide", Kramer discusses suicide with Jerry, and says that he'd give someone 72 hours to come out of a coma before all his property is up for grabs. However, in the episode "The Comeback", Kramer tells Jerry that he never knew that people could come out of a coma.
Add timeDandude776 1
Continuity mistake: At the beginning of the show, when Jerry is having a massage, his hands are in front of him, under his chin. The position of his fingers change considerably after the masseuse says, "I don't know" but then return to the original position in the next shot.
Character mistake: When George and Elaine go to the coffee shop after the movie without Jerry, they establish that Elaine moved to NYC in 1986. Then they make fun of the way that Jerry throws up; both imitating Jerry. The "Dinner Party" episode is after the "The Dog". In the "Dinner Party" episode, Jerry brags that he hasn't thrown up since June 29th, 1980. The black and white cookie ended this streak. Elaine would not have been around to see this, not arriving in NYC until 1986.
Continuity mistake: When Jerry's sitting with George in the hospital talking about George's jacket, as Jerry says "no, I tried it on, it fits good", he's gesturing with his left hand, which he then puts in his lap. From the reverse angle though, his left hand's still raised, then he lowers it again.
Add timeJon Sandys
Continuity mistake: This mistake is in the Calzone episode. Towards the end when George walks in and his boss is looking around for the smell of calzones, George is holding a bag in his hand. In the next shot that shows the back of the boss's head the bag is now on top of a box that George is carrying. When it goes back to a close up the bag is in his hand again.
Factual error: During the entire series, the view of Jerry's door from the hallway is of a flat wall with the door in line, yet from inside the apartment, not only does the kitchen angle into the hallway, but Jerry's fridge is recessed into the wall. The wall behind it should be blocking the hallway completely.
Continuity mistake: At the beginning of the episode, when Puddy is farewelling Elaine on the street, he is standing on the sidewalk and leaning through the driver's window. The following shot when she pulls out quickly, you can see through the windows of the car that Puddy is nowhere to be seen.