At the party to announce the engagement, Stanley is fixing drinks, and opens two Cokes which spray all over him. In the next shot, the bottle opener has disappeared from the kitchen cabinet, and a bottle of Brandy appears in his hand, which he must put down to wait on the next person.
After experiencing a nightmare of the wedding going wrong, Stanley wakes up hungry and decides to take 1 cookie in his hand. When he gets into the kitchen and sees Kay, he then puts 3 cookies on the kitchen counter.
When Stanley hangs up the phone at the end and turns to Ellie, his jacket has a spattering of confetti on the back. Later, when he dances with her, it is gone.
Near the beginning, when the Banks family is having a meal, the length of the candles on the table changes from long to short and back to long.
When Stanley answers Kay's phone call, there is a shot of the folding chair, and it is clean with nothing on it. However, in the next shot when he ends the call and goes back to Ellie, the chair has confetti all over it.
At the meeting with the caterer, Stanley spies a $400 cake and pointedly says they do not want one. Later Ellie insists, and they get a cake after all. However, wedding plans often evolve over time; the bride's mother changing her mind about having a cake certainly is not a Goof.
At the party to announce the engagement, Stanley is fixing drinks and opens two Cokes which spray all over him. In both cases, but especially when he opens the second coke, it is obvious that the spray is coming from the wall cabinet, not from the coke bottle.
When Stanley is first trying on his old tuxedo, the door to his bedroom is slightly ajar. Ellie then approaches the door and secretly watches him getting dressed through the opening of the door. However, Ellie could not have seen him, as Stanley was behind the door away from view and not in front of the door's open gap.
When a guest is in the kitchen as Stanley is preparing drinks, there is an open cabinet door. The guest tries to slam it shut two times; however, it doesn't close, and there is no sound. Stanley also tries to shut it with the same result. Apparently, it was rigged it so that it can't be closed; in doing so, the metal parts on the door which would have caused it to make noise must have been removed.
When the Banks are driving to meet Buckley's parents, Ellie says they are looking for the house numbered 394. When they get to the destination, the number on the house is 709.
When Stanley (Spencer Tracy) is fixing drinks at the engagement party one of the party goers asks, "When are you gonna make your speech, Herb?" "Herb" is the first name of Buckley's father.