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.
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.
After leaving Las Vegas,the characters Andy and his mom would drive from Southern California arriving into San Francisco via the eastern entrance, the San Francisco-Oakland Bay Bridge. The movie shows them entering San Francisco from the northern entrance across the Golden Gate Bridge, the more well known bridge, but an out of the way circular route from southern California.