Continuity mistake: When Nora is explaining to her friends at lunch that she and Luther are skipping Christmas, her friend asks her "When do you leave?" without Nora ever mentioning that she and Luther were going on a cruise.
Continuity mistake: During the scene when the Polar Express slides across the ice and the conductor is telling the train controllers to head for the tracks, the distance between the train and the tracks keeps changing.
Continuity mistake: Near the end, Mike is hanging the glass angel he got from Artie on the tree. Nina comes in through the front door, leaving the door chain hanging (unlatched), yet, in the very next shot the chain is on.
Continuity mistake: In the scene where Ben Affleck gets hit in the head by the shovel in the beginning, when the shovel is about to hit him, the paper is not on fire for a split second. Then when he's on the ground it's on fire again.