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.
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.