When Debra asks Frank if he had found a parking space she accidentally calls him Ray. "Did you find a parking space Ray?"
The colors "Lemon Meringue" that Frank paints the house in and "Chantilly Lace" that Ray wanted were both references to the X-files episode 'Clyde Bruckman's Final Repose', for which Peter Boyle won an emmy for portray the title character.
When Raymond is throwing the Twix bars on the bed, they rearrange themselves halfway through the scene.
Marie's canister can be seen in Ray and Debra's kitchen. Two episodes prior, in "The Canister", she and Debra argued over where the canister was, and once it was found at Ray and Debra's they went to great lengths to smuggle it back into Marie's home without her knowing it. This is caused by "The Canister" airing before this episode, despite being produced after.
How is it that the canister didn't get the least bit bent up when Debra was stuffing it in the garbage can and jumping up and down on top of it to make it stay in the garbage?
Marie acts like she is reading from Raymond's diary, however from the angle that she's holding it, it's obvious that there's no writing on the page except for a standard header on every page. Raymond also doesn't write anything when she asks him to amend the entry.
Robert says they left him at a gas station in Arizona, but in "Traffic School," he says they left him at a station in New Mexico.
In the beginning of the episode when Robert is greeting Lois, he bends down and accidentally kisses her on the lips.
Later on, when Lois and Warren are arguing, he mimics her about the kiss. This is strange, because when they kissed Warren was outside. So unless someone told him about it, he shouldn't know they kissed.
Nitpick: When Robert was having a box of Bugles, he didn't touch it to his chin. After offering Raymond a Bugle, he touched another one to his chin.
At the beginning of the episode Ray is reading 'Newsday'. If you look closely at the front page headlines, you can see it is the same paper that Frank was reading at the kitchen table during the previous season's episode of "What's with Robert?".
At the beginning of the episode, Debra is talking about how much she enjoyed Italy because the whole family got along so well. It's a bit of a stretch to say that, especially since Ray was in a horrible mood up until the last couple of days, and Marie was her typical nagging self toward Debra throughout the trip.
When Ray is complaining about the new wallpaper stripes being thinner than the rest of the walls, look closely and you'll see that is it actually the exact same.
When Robert is eating his peach gelato for the first time, he does not touch it to his chin. Obviously, it's not very smart to touch ice cream to your chin, but it's still very strange to see, because Robert never goes without this little habit.