Continuity mistake: When Lumburgh meets with the Bobs, Dom is sitting beside him during the entire meeting. However when Bob Slydell pulls Lumburgh's personnel file, Dom has disappeared from the room.
Continuity mistake: Towards the beginning of the movie when Peter Michael and Samir are at the diner for the first time, Peter notices Jennifer Aniston and she has two full plates of food in her hands. Then she gets into some heated argument with her boss and they cut back to Peter and the guys again and back to Jennifer but this time she doesn't have the plates.
Revealing mistake: When the guys go to see Tom at the BBQ, he has his head in a support cage. Every time he moves, and particularly when he laughs, this cage moves around and wobbles. The point of these cages is to keep the head still and in line with the spine, and are bolted into the bone itself. Therefore, not only should it be impossible for it to be moving, it would seriously hurt if it was.
Continuity mistake: In the scene where Peter, Michael and Samir are consulting with the crack-addict magazine salesmen, you will notice it is dark outside. The next scene is Bill's birthday party during the day at the office where they discover money is missing. Then the next scene is back at Peter's apartment continuing the scene where it happens to be dark again.
Continuity mistake: In the scene in the beginning of the movie where Peter is talking to Bill about the TPS reports, we see his computer monitor and the text on it is blue. Later, when he's trying to shut his computer down to escape work early, we see that the text is now yellow.
Continuity mistake: When Joanna and Peter first meet in Chotchskies, note the differences in Joanna's upper body (placement of hair on shoulders, placement of arms and hands, shoulder tilts, and so on) as the film cuts a number of times from Peter to Joanna and back again. For instance, we see her grasping her arms, and a split second later her arms are at her side.