Continuity mistake: The large spoon and fork in Frank and Marie's kitchen change positions, right to left, and up and down. In some episodes the fork is on the right, and in others it is on the left. In other episodes, the fork is higher or lower than the spoon. At other times, the spoon and fork seem to be larger than at other times. It is obvious when she removes one of the utensils that they have never been moved - the wallpaper underneath is a different shade from fading. If these were moved at subsequent times in the supposed feud, the difference in wallpaper fading would be seen.
Factual error: When Ray cuts in front of a woman at the ATM, she runs to get a cop. She comes back with Robert. The problem is, Robert is a New York City cop, and Ray lives in Nassau County, which is not in New York City. Robert has no jurisdiction, and would not be patrolling in Nassau County.
Continuity mistake: Prior to bringing Ray up for the role-playing exercise, the parenting teacher erases a circled phrase from the chalkboard. Throughout the scene, the chalked circle flips several several times between being totally erased and having a faint outline left over.
Continuity mistake: In the scene where Debra tells Ray her parents have separated and he laughs, later on in this scene he tells Debra that he got free candy from the broken vending machine at work. When Debra leaves the room, Ray starts taking more candies out his pockets and throwing them on the bed. Take notice of the position of the sweets on the bed. Now just after the close up scene of Ray scratching his head, look at the position of the sweets. Totally different. One or two are actually closer to the end of the bed, whereas in the scene before, they were more further on.
Continuity mistake: Marie comes over with a cake shaped like a cross. In almost all the scenes where the family is sitting at the table different pieces of cake are missing. In some of the camera angles there are no pieces of cake cut from the bottom yet when the cake is seen from other angles there are.
Factual error: Robert begins as a SGT in the NYPD (later promoted to LT). However, he has issued speeding tickets in his brother's/parent's neighborhood. The family Barone lives in Lynbrook NY. Lynbrook is part of Nassau County, Long Island, which is not part of NYC. Robert would have no jurisdiction to issue speeding tickets there.
Factual error: Robert's voyeuristic neighbors are using the same elevator as Robert does and tease him about seeing him and Amy through his bedroom window. But if they were able to see into his bedroom, they would not be using that elevator; it would be in another building. From the outside shot of his apartment building, it would be impossible to look into his bedroom.