Plot hole: Lee and Dawn overstay their tourist visa in the US, then fly back to the UK for the Office Christmas party. They then get into a taxi to go out to the airport in order to return to the US. They're kidding themselves. As I know (to my cost) when you overstay a tourist visa, the US Immigration Service finds out when you check in at the airport on departure. They'll be refused reentry, and probably barred from entering the US for up to six years. (I got a three year ban.) Neither Lee nor Dawn could possibly be unaware of this nor think they could beat the system as they would have been arrested when they checked in in Florida on departure (as I was), and they would have remained in small holding cells until the paperwork banning their return had been processed and their passports stamped 'Invalid for U.S. Entry', as mine was. (All this takes about seventy two hours, so they'd have missed the Christmas party anyway.) The mistake is NOT that they were able to leave the USA - that is explained (it's still not possible, but in the context of the show and the suspension of disbelief we are meant to believe it) the mistake is that they are on the way back to the airport to return. That's absurd. They would have been under no illusions as to their banned status re reentry to the USA.
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.
David Brent: I don't look upon this like it's the end, I look upon it like it's moving on, you know. It's almost like my work here's done. I can't imagine Jesus going 'Oh, I've told a few people in Bethlehem I'm the son of God, can I just stay here with Mum and Dad now?' No. You gotta move on. You gotta spread the word. You gotta go to Nazareth, please. And that's, very much like... Me. My world does not end within these four walls, Slough's a big place. And when I've finished with Slough, there's Reading, Aldershot, Bracknell, you know I've got to... Didcott, Yately. You know. My... Winersh, Taplow. Because I am my own boss, I can... Burfield. I can wake up one morning and go 'Ooh, I don't feel like working today, can I just stay in bed?' 'Ooh, don't know, better ask the boss.' 'David can I stay in bed all day?' 'Yes you can David.' Both me, that's not me in bed with another bloke called David.
Gareth: That's one reason why gays shouldn't be allowed into the army. Because if we're in battle, is he going to be looking at the enemy, or is he going to be looking at me and going "Ooh. He looks tasty in his uniform." And I'm not homophobic, all right? Come round, look at my CDs. You'll see Queen, George Michael, Pet Shop Boys. They're all bummers.