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: 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.
Continuity mistake: On Ray's house, the small window at the base of the stairs is not seen in the outside view typically shown before and after commercial breaks.
Continuity mistake: In "The Suitcase" Ray says he bought wooden spoons and forks. In other episodes the spoons and forks are metal.
Continuity mistake: Throughout the series when the exterior of Ray's house was shown there are steps leading to the front door. In one episode Ray's mother drives a car through the wall and when she drives off there are no steps. Where did they go?
Continuity mistake: The exterior of Ray's house does not fit with the interior, even before Marie drives through the front of the house with The Car. The windows are in the wrong places and the door placement is off.
Factual error: Robert, as a police officer in NY State, is bound by law to carry his weapon at all times. Robert is never seen with a firearm, not even when in uniform. A police officer would not have his sole sidearm strapped to his calf or ankle under his pant leg, making it hard to access in a situation where he would need to be able to draw it at a moment's notice.
Continuity mistake: The garage door at Raymond and Deborah's house has two different sets of windows in some of the same episodes. One set of windows are lateral and the other set are half rounds.
Continuity mistake: In living room scenes, there are two windows. One to the immediate left of the door and one by the landing of the staircase. When they show the house from the outside, there are two large windows on either side of the door.
Continuity mistake: Throughout the show the twins' names changes from Matthew and Gregory to Michael and Jeffrey.
Other mistake: In the first episode "The Pilot", the outside of Raymond's house and the bedroom both look different than in the rest of Season 1.
Character mistake: At the very beginning, when Ray is picking up the food from the floor, he and Deborah refer to their kids by different names. They call one kid Matthew and the other Gregory. Yet we know the twin boys as Michael and Geoffrey Barone. Also, in the same shot when he says, "Clean up Isle 2," you can see one of the bowls fall on the floor, and the second bowl is launched from the highchair without anyone touching it. (00:00:16 - 00:00:40)
Other mistake: The kitchen in Marie's and Frank's house is completely reversed in this episode than in the rest of the series.
Visible crew/equipment: The overhead microphone slips into the view many times.
Suggested correction: This needs to be way more specific.
I Love You - S1-E2
Continuity mistake: Debra is sitting up in bed holding a magazine and talking to Ray. She quickly puts the magazine down in her lap as she says something to Ray but then in the next shot, she's holding the magazine up again. (00:05:25)