At the last minute, Tom decides to switch presents between his father and his brother-in-law George. When Tom is handing his dad his Christmas present, in the background George is opening his. Dad opens his present, then the scene goes to George's wife handing him the present to open for the first time.
When Adam starts reading "The Night Before Christmas" to the children, he is already in his bathrobe. But later that night in several scenes including the confrontation with son in the study, he's still wearing a suit.
Based on some statements in the dialogue, this film is set in New England. But the actual location of the filming is inadvertently revealed in one of the opening shots: just as Veronica Hamel's name appears on the screen, the "Chagrin Falls Bakery" clearly appears in the background, showing the actual filming location to be Chagrin Falls, Ohio.