Continuity mistake: Before the fire scene, the rain gutter is on fire in several places. But when the rain gutter gets disconnected, the fire in the rest of the rain gutter mysteriously disappears.
Continuity mistake: In the 'race scene' near the end of the film, just before Greg and Jack go their separate ways, you see Larry (who is sitting next to Greg) say, 'Oh, look, there's Jack. Hey, Jackie,' and he waves. Then it cuts to Jack, who is looking at Greg, and then it goes back to Greg, and in the background you see Larry and he is unfolding a newspaper and starts reading it. Then it goes back to Jack, and then back to Greg, where you see Larry with his hands on the dashboard, looking at Jack. So what was with the newspaper? Where did it come from? How did it disappear so quickly?
Audio problem: When Jack is talking to Greg inside the changing room, Jack is saying, "I'll be watching you", but his mouth is still moving saying something else. (00:51:40)
Plot hole: The fake Jinx wouldn't be able to get into the den, the door was closed.
Continuity mistake: During the scene when everyone is gathered around discussing the whereabouts of Mr. Jinx, Jack announces "We'll just have to reschedule..." Debbie jumps up from the couch and when she does she hits the coffee table causing one of the edges of the table to fall and hit Denny's knee. The next shot the edge is back in place off Denny's knee and Denny has slightly changed positions.
Continuity mistake: Before and throughout the scene where Jack demonstrates his hidden cameras, the lemon and cherry in Greg's glass keep moving around.
Continuity mistake: When Greg is trying to open the suitcase, the top pouch is empty, when the delivery man drops it off, and when Jack tries to open it, the top pouch is full.
Other mistake: Near the end of the movie, Greg says he's in row 8 on the plane. But when he's on the plane, we see there are only about 7 or 8 rows behind him. If the plane had only 15, 16 rows, the plane wouldn't have that middle section of seats.
Other mistake: When Greg asks the kid behind the counter if they have the Nicorette patches, he says no, and hands him a pack of the Nicorette gum. However, the package to the left of the gum, and possibly to the right, are patches.
Continuity mistake: When Pam is ringing Greg near the end, Jack is watching from the side, and it is obvious how much longer his hair is compared to the rest of the movie. His hair is quite short in the rest of the movie. So it is obvious (since he looks younger in that scene) that that scene had been shot near the start of the filming.
Continuity mistake: For the first half of the movie, the cat's tail changes colour from black to light brown, to black again.
Continuity mistake: When Greg is at the airport's lost luggage department you see the baby chuck up on him but you can see it actually comes from too low down. (00:08:00)
Continuity mistake: At the dinner table when Greg is trying to open the champagne, Pam look straight ahead startled for a second, then in the next frame she is talking to her dad again. It looks like she is seeing the urn hit before it is in the film.