At the very end of the movie after Daphne knocks the cake off the cliff, it hits Stuart on the head. Before it hits Stuart he is placing headphones into his ears. When the cake hits him the one for his left ear is hanging down and is all full of cake, however when he looks up both headphones are in his ears.
When Daphne and Joe are watching the old movie classic a scene is playing and the character says "I should have married him" just before Joe kisses Daphne. After they kiss and we see a shot of them from behind the same scene of the movie is playing again.
While Joe and Daphne are making out on the bed on their wedding day, Daphne is in stocking feet before cutting away from the scene. When the camera returns to the bed for the rest of the scene, she has her red pumps on.
In the massage scene when Milly is storming out, Maggie wraps her towel around herself. Right after, when the camera focuses on Daphne and Maggie, she doesn't have the towel wrapped and ends up wrapping it around herself again.
In the scene where Daphne is following Millie and Johnny on their first date, at one point Daphne ducks down to avoid being seen by Johnny. When doing so, we see the dog in the back seat and the head and arm of the "stunt driver" in the driver's seat.
In the scene where Daphne is trying to get Milly to pick up the phone and they are both moving the furniture, Daphne is sliding the couch over and it actually keeps sliding for a second (due to someone pulling on the other side) even when Daphne quits pushing.