When Peter goes in to get interviewed for the first time by the Bobs, there is no shade or blinds covering the office window. You can see the office through the glass. However, when you see Peter first go in, the window is not see-through and has a blind/shade covering it.
When Peter and Joanna are having lunch at 'Flingers' Joanna's menu changes locations between shots. First it is on top of her plate, then it is beside her plate. This goes back and forth several times. Her arms also change position throughout the scene.
Near the end of the movie, Before the scene in which Milton speaks to Lundbergh's Secretary asking for his stapler, an outdoors shot of Initech is shown. In this shot, Peter's car can be seen parked in front of the building in/near Lumbergh's spot. After the scene with Milton, Peter pulls into the parking lot.
When Lawrence is coming over to Peter's apartment because Peter doesn't want him yelling through the walls, he comes out of his apartment with a beer in his left hand. He grabs the doorknob on Peter's door with his right. When Lawrence enters, the beer is now in his right hand, and his left hand is on the doorknob.
When Peter, Michael, and Samir go for morning coffee, Michael pours tons of sugar packets into his coffee. The position of the empty sugar packets changes in one shot, moving to the side of his coffee cup where the rest show the packets in the front.
When Lumbergh pulls into his parking spot after the opening credits, the sign is "Reserved Parking, Bill Lumbergh, Division V. P. . About half way through the movie, Peter pulls into Lumberghs spot and the sign has changed to" Reserved Parking, Bill Lumbergh".
When Peter and Michael are sitting in Peter's apartment with beers in their hands, the label on Michael's seems to switch which direction it is facing, depending on the camera angle. Two shots have it facing the camera, and the last one has it facing away, all while Michael never moves his hands. Further, Michael has dribbled beer on his shirt without having taken a drink during that part of the scene.
When Peter goes to see Bob and Bob, he walks into the room, and one of the chairs is facing the camera. After he gets himself a glass, he turns around to go sit at the table. All the chairs are facing he table, including the one that was facing the camera, even though it was untouched.
When Peter turns to Lumbergh at the beginning of the movie and Lumbergh says, "Good morning, Peter," Peter is wearing a yellow earplug in his right ear, but it's not there for the rest of the scene. In an earlier draft of the script, Peter puts on earplugs to drown out the sound of Nina, the receptionist, answering the phones.
In the post-interview briefings where the "Bobs" express their support of Peter, and Bill Lumbergh is hesitant to heed their advice, the mood abruptly shifts to the Bobs questioning of Bill's business acumen. In the close up shot of Bob's hands, he pulls Peter's file away to reveal Bill Lumbergh's directly beneath it - both showing in close-up that each has an accompanying employee photo in the top right-hand corner. In the following shot from further away, Bob performs the same task, however, this time as he slides Peter's file away, he hesitates, and in an action that differs from the close-up shot, he rotates the file underneath to a readable position, where we also now see that Bill Lumbergh's file no longer has the ID photo anywhere on it.
When Peter first enters the room with the Bobs to re-interview for his job, he goes to the back to get a glass of water. As he does this, you can see that the chair he will be sitting in is slightly pulled out, yet as goes to sit down, the chair is entirely pushed in.
At the end of the printer destruction scene, Michael runs back to jump on the printer one last time. Right before he runs back to attack the printer, it is shown open and nearly empty, but when he jumps on it, it's full of parts again.
When Peter and Samir are dragging Michael away from the printer, he is holding the power cable. He drops it when he attempts to attack the printer one more time, but in the shot of the three of them walking back to the car, he's holding it again.
When Tom is talking about his "jump to conclusions" mat, the plastic army men on the cubicle wall are seen in one position. After Tom leaves, there is a close up of Peter. Here the army men are clearly in a different position.
When Samir has his battle with the printer, arguing about its paper jam, he grabs at the sheet of paper stuck in it. When the camera viewpoint switches to a longer shot, when you see his arm next, he isn't holding the sheet of paper. The sheet of paper isn't seen again.
When Peter is signing his confession and enclosing the traveler's checks, at least two of the checks have the same number on the top right corner. Obviously different checks, even the same amount, would have a different check number.
When Peter shuts down his computer, it shares characteristics
with both Macintosh and DOS-based computers, including a hybrid Mac/Windows GUI, an A: drive and a C:\ prompt. The movie is set in a generic, universally-identifiable world, and the hybrid computer is clearly a carefully-planned gag based around that theme, rather than a goof.
When Peter takes down the banner that says "Is this Good for the Company?", Milton has to look across the office at Peter. In a previous scene following the introduction of the Bob consultants, Milton is shown directly under the banner. However, throughout the movie, Milton talks about the fact that his desk is constantly being moved around the office. There also might have been more than one such banner.
The mismatch between the words and the lips when the doctor has the heart attack isn't a goof. It was intentionally done to show that Peter was "in a trance" or was "under". Reality, as he knew, it had been changed.
Peter uses two different buttons to advance through his messages. When Peter motions to leave the answering machine, the messages automatically stop without him pressing any buttons because he pushed the delete button.
The big settlement that Tom got from the drunk driver wouldn't have played out the way it did in the movie. This is because it actually would have been Tom's fault because he backed out in front of the drunk driver just before the collision. In addition, Tom is shown heavily drinking just before the incident, making it likely that he had a high blood alcohol level as well.
As Bob pulls out Bill Lumbergh's file, with accompanying photo ID, during the post-interview discussions, we see that Bill is wearing the exact same shirt/tie/suspender combination during the meeting as he is in the picture. (Even though this isn't a "goof" in the strictest sense of the word, it is still an unlikely occurrence that, considering the Lumbergh was somewhat of a clothes horse, he would just happen to be wearing that exact outfit, and on that exact day.)
Tom is hit by a car, rendered paraplegic, released from the hospital, and awarded a huge settlement - all in the space of one week. While he hasn't gotten the actual check yet, just getting it approved in that time frame would require an exceptionally competent insurance company.
When Tom is in the wheelchair at the party celebrating his release from the hospital, there is extensive bruising and laceration to the left side of his face. Tom's car was hit from the right side, and the force of this impact would have thrown the upper portion of his body to the right, where there would be no portion of the car that could cause this type of injury.
The only way Tom could have received this kind of injury is if his car had been hit on the left, thus throwing the left side of his face into the driver's door.