Continuity mistake: Often during the show, the viewpoint will switch between cameras to show people from different angles. The problem is, the show is meant to be seen as a documentary, and filmed "for real", meaning these camera switches would reveal the camera that must have been taking the previous shot. No cameras are ever seen, and as a "documentary" it can't be said that the filmmakers could ask the characters to stop in mid-conversation while they moved the previous camera out of the way.
Continuity mistake: After Gareth hits Tim on the head with his newspaper the following shot shows that the briefcase and newspaper have swapped hands. (00:04:25)
Continuity mistake: When Donna comes in late and David is asking her where she has been, as it changes shots between Donna and David, in the background Dawn's right sleeve changes from being down to up at wrist height several times but she is in the same posture all the time.
Continuity mistake: In the scene with David and Gareth in David's office, David gives a hole-punch to Gareth as a souvenir. The hole-punch has a guide accessory sticking out of it (to punch holes in the middle of different sizes of paper), which is adjustable. At the beginning of the scene it only sticks out by about 2 cm, but by the time David hands it to Gareth it is about 5 cm - even though no-one has touched it. (00:15:35)
Appraisals - S2-E2
Continuity mistake: In Keith's appraisal David asks him about 'The Q & A'. In the shot of Keith answering with 'I thought you filled that in', David's right hand is off the paper. In the next shot his hand is clutching the paper. (00:12:35)
Continuity mistake: During David Brent's dance, towards the end of the dance Rachel laughs. When the camera cuts back to her in the background she is straight-faced.
Answer: In the Christmas specials, David states the documentary crew stitched him up. In other words, he was made to look like an idiot by the way it was put together, but in actuality, he may not have been as bad as the documentary had made out. In addition, it's clear he let his upcoming celebrity status get to his head, something that would not have happened prior to the documentary crew's arrival. At the end of series 1, he mentioned one of his achievements was cutting expenditure without losing any staff.