Continuity mistake: In the scene where Hal goes to congratulate Ralph on getting back together with Rosemary, the amount of dandruff on Ralph's black shirt keeps changing between shots.
Continuity mistake: When Rosemary gets into Mauricio's VW at the end, the car drops down rather significantly (for comedic effect). However when Li'iBoy (who is heavier than Rosemary) and Ralph were in the right side of the car when it pulled up to the house, it wasn't leaning at all.
Continuity mistake: As they're leaving the house at the end, just before they drive off, they show the car from front. Behind them, you can see Jason Alexander with his hands in his pockets. Next shot is from behind the car and he has his hand up in the air waving. (01:40:50)
Continuity mistake: In the scene where Gwyneth is stripping at the end of the bed they start out with a front shot. She puts her hair behind her ears and there is none on the front of her. Then they switch to a back shot. She now has her hair pulled forward where it is lying on her chest.
Continuity mistake: In the scene in the restaurant when Hal is about to find out what Rosemary really looks like, Rosemary is sitting with a green napkin in her lap. When she starts to fall, from the booth breaking, the napkin is still in her lap. When Hal rushes over to help her up, the napkin is nowhere in sight.
Continuity mistake: In the scene when Gwyneth Paltrow and Jack Black are in the restaurant, you first see her with a clip in her hair, but after she falls down it is gone.
Continuity mistake: When Hal is sitting in the elevator with Tony after it stopped, he is talking about a "severance pop." In this shot, the collar is his shirt is sitting out over his black waistcoat. But in the next closeup, it is nicely tucked under the waistcoat. (00:13:15)
Continuity mistake: When Hal's dad is on his deathbed, his hospital gown is wrinkled, including a large fold across his stomach. There is then a shot of Hal with his dad in the foreground and the gown is perfectly smooth. The next shot shows the dad again and the wrinkles are back. (00:03:20)
Continuity mistake: After Hal's hypnosis is broken at the restaurant, he's outside talking with Mauricio and then Katrina walks up to him saying he never called her back. During that line walking up, she still looks fairly attractive (but not nearly like the supermodel look Hal saw in the cab). Then the camera is on Hal a second then back to Katrina and suddenly now she looks fully "unattractive" for the rest of the scene. She should have also looked fully just as unattractive when first walking up to Hal as well.
Suggested correction: The version of Katrina we see the second time, as she's walking, doesn't change when she starts talking to Hal. Her hair is pulled back and into a ponytail instead of full and blonde like the first time we saw her. The only difference is we don't see her teeth until she starts talking. The camera also never cuts away from Katrina when she's seen walking up to Hal and when she first talks to him. It cuts to him after we see she's less attractive.
Yes, however, her mouth closes close up (without showing her teeth for a second or two), and she still looks like a different person than when first walking up. Maybe it's just the way I see it (maybe I caught Hal's hypnosis).
Continuity mistake: After Mauricio hits his head after explaining to Hal about being beat up in gym class, some of his shake-on hair becomes dislodged, leaving five or so bald spots on the back of his head. In the very next shot from the back, the bald spots are filled in again.
Continuity mistake: In the scene with Hal and Mauricio in the bar, they both have a beer. In the shot where Hal asks if things are okay between Mauricio and his girlfriend, Hal takes a drink from his beer and Mauricio is holding his beer down by his chest. In the next shot Hal is suddenly not drinking his beer anymore and it is out of sight and now Mauricio's beer is by his mouth. (00:06:55)