Continuity mistake: In the scene where Hal is confronting the two guys that made fun of Rosie he points to Rosie outside the restaurant and her shoes change from brown and black clogs (which is what she was wearing throughout the scene) to a plain black slide. Watch, it is totally obvious because they show her shoes several times before they suddenly change.
Continuity mistake: At the DoubleDoor Inn, where Rosie is seen dancing with the guy with spina bifida, we see the other guests applaud and approach them once they have finished dancing. And if you look closely you will see that Hal joins the crowd at the right hand side of your screen. But as it cuts to the next shot where Rosie is walking away from the crowd, we see Hal catch up with her from the opposite side where he was standing with the crowd.
Continuity mistake: In the first club scene, Jason Alexander is dancing with a swaying woman, behind them is a woman wearing a headband and sleeveless pink top; as the camera pans around the corner to Hal's new dance partner who is holding on to the railings, the same girl with a headband is dancing next to them, only this time with a different guy.
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: 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: 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.
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.