Factual error: When Max goes to the bait shop with John and they are talking to Chuck about him going over to Ariel's house for Thanksgiving, they ask him if he saw the Blackhawks game, saying that it went into double overtime. NHL games only have one overtime unless it is a playoff game.
Continuity mistake: After her wedding to Jack Lemmon, Ann-Margret says goodbye to Walter Matthau by kissing him on the cheek. When the camera shows her, she places her left hand on his face. When the camera shows him, her left hand is on his shoulder. When the camera returns to her, her left hand is back on his face again.
Revealing mistake: In the scene where Max is trying to find the source of the bad smell in his car, a shot from behind shows a view out the windshield. The column shifter is in Park even though Max is driving.
Continuity mistake: When the snow falls from the roof onto the IRS agent, he falls down and rolls forward, and almost all of the snow lands several feet behind him. When the shot changes to a side view, he is now closer to the house again, directly under the snowfall.
Continuity mistake: In the final scene of the movie, Max has left home for the evening, leaving Jacob alone. Jacob spies Melanie next door and is invited to come over. Jacob runs next door through heavy snow. Yet earlier that day, the wedding had occurred in Springlike conditions, snow nearly gone.