In the opening scene of the movie, Joyce crumples up an M&M's bag in her hand, and then the next shot shows her putting this bag onto her nightstand, only it's not crumpled up, and is actually flattened out.
When they pull off the road in Tennessee with a possible flat tire the license plate on the rental was from New Jersey. At the airport in California when they pull in to return the rental it shows a New York tag.
On the way to see her old boy friend, Joyce uses Ben's name, not Andy's, when she is talking about not having seen him in thirty years.
The 50-ounce steak is described in subsequent dialogue as a "4 1/2 pound steak." A 4 1/2 pound steak is 72 ounces. A 50-ounce steak is 3 pounds, 2 ounces.
In the first hotel room, Joyce turns off the lamp, and it is clear that she is not actually flipping a practical switch, but making a finger motion to cue the light change.
When Andy and Joyce first ring the doorbell on the house in San Francisco, the shot is of them from outside the house and their voices and the bell sound accordingly. When they ring the bell the second time, the shot is from inside, and their voices thus sound like they are on the other side of the door, correctly. However, the bell still sounds as though the microphone were still outside.
When Andy and Joyce first ring the doorbell on the house in San Francisco, the shot is of them from outside the house and their voices and the bell sound accordingly. When they ring the bell the second time, the shot is from inside, and their voices thus sound like they are on the other side of the door, correctly. However, the bell still sounds as though the microphone were still outside.
When Joyce storms out of the motel room in the middle of the movie, the sound of the door opens. But she is seen outside in the next shot behind Andrew and the window and then the sound of the door slamming shut. The door slamming should have happened earlier.