Corrected entry: In the scene where Max Goldman is sprayed by John Gustafson with a water hose, Max's son, Jacob says something to the effect of: so what dad, Gustafson has started every fight since 1940? Max replies: no, since 1938! Later on in the movie, when John and Max are fighting on either side of their property fence (when John has the axe), it was revealed that they were fighting since 1937, not 1938.
Corrected entry: The morning after John and Ariel make love, he goes down to the kitchen to make himself breakfast. He grabs one egg out of the fridge three different times, but in the subsequent shot we see him cooking only two eggs. What happened to the third egg?
Corrected entry: In one of the practical jokes that the characters played by Walter Matthau and Jack Lemmon play on each other, Lemmon's character puts a cat on the front seat of the Matthau character's car. He tells the cat to scratch up the front seat, which he does so bad the stuffing is coming out of the seat. But in the next shot of the front seat it's undamaged.