Continuity mistake: In the scene just before Joey goes into the shower, when he is thanking the director for the opportunity, the camera shot goes back and forth between Joey and the director several times. During this series of shots, the part in Joey's hair switches sides nearly every time. It appears that the entire shot is reversed - in the closeup, the shower curtain is on his left and the shadow to his right is sharply focused. In the lower (long) shot, the curtain is to his right, and the shadow on his left is more focused. (00:13:05)
Revealing mistake: In the episode where Joey is doubling Al Pacino's butt you can clearly see his shadow when he's shooting the scene in the shower, and he's wearing boxer shorts. (00:13:20)
Other mistake: When Joey announces that he has a job in the new Al Pacino movie, Ross is holding a bottle of peach Snapple with part of its brand name whited out, so it reads "S pple" on the label. (00:13:50)
Revealing mistake: When Joey is filming his scene for the movie, look behind the director to see a box saying 'Monica' indicating that it was shot on the Friends set rather than Al Pacino's set. (00:16:30)
Continuity mistake: When Chandler's partner says she's going to be late for Andrew she has her hands in front of her. Camera changes and now one hand is up by her hair. (00:18:15)
Continuity mistake: At the very end when Monica is in bed, her grip on the bed clothes changes between shots. (00:23:10)
The One with the Blackout - S1-E7
Continuity mistake: At the start of the scene where the group disclose the weirdest place they've had sex is, Monica has her hands together on her lap. In the next shot, they are underneath her legs. (00:05:30)
The One with the Blackout - S1-E7
Other mistake: Ross says that he was at Disneyland with Carol and got caught hooking up on Small World and asked to "never to return to the Magic Kingdom." Disneyland is in California and the Magic Kingdom is part of Disney World in Florida. (00:06:10)
The One with the Blackout - S1-E7
Revealing mistake: When Rachel first meets Paolo she's looking for the cat in candlelight, holding the candle in front of her. You can see her shadow on the wall, as well as the shadow of the candle, revealing that the light is not coming from the candle. (00:07:25 - 00:14:30)
The One with the Blackout - S1-E7
Continuity mistake: In the scene where Joey is standing with candelight over Ross' neck, the candle is full length, but in the next shot it's only half length. (00:13:00)
The One with the Blackout - S1-E7
Other mistake: Phoebe says she was last to know Monica had a crush on Joey when he moved in and Joey acts as though he never knew this. However, when we see him moving in a later episode, he knows Monica has a crush on him, and he is under the impression that Monica wants sex and so strips off in the living room while Monica is preparing some drinks for the pair. (00:13:10)
Suggested correction: I may understand the situation but please do correct me if I'm wrong. Basically in the flashback episode they saw each other in the hallway and smiled at each other. They would've both got the impression that the other one liked them. However, after the lemonade incident he would have then got the impression that he was wrong and Monica didn't actually like him. Finally, Joey heard that she did like him and got a bit confused and a bit happy at the same time.
The One with the Blackout - S1-E7
Continuity mistake: Rachel takes the cat to apartment number 8 and Mr. Heckles opens the door. However, in this episode, the girls' apartment is labeled number 5 which means that number 8 is above them. In later episodes, Mr. Heckles always says that the noisy girls upstairs are keeping him from doing things. [It makes a bit more sense later on in the series when Monica and Rachel's appartment changes to number 20, which is when Mr Heckles starts to complain about the noise (although in the flash back episode when Phoebe is still living with Monica it seems apparent that they actually know Mr Heckles, which Phoebe shows no sign of when she and Rachel are looking for the owner of the cat).] (00:13:40)
The One with the Blackout - S1-E7
Other mistake: When Ross and Rachel are out on the balcony alone for the first time, there are no lights on in NYC apart from candle lights. Look in the BBQ behind them though to see a very bright and very white light reflected in the paintwork. (00:13:50)
The One with the Blackout - S1-E7
Revealing mistake: When Chandler is choking on the gum, you can see it is still in the left side of his mouth in a huge lump. (00:16:45)
The One with the Blackout - S1-E7
Continuity mistake: During the Monopoly game (deleted scene), right after Monica says, "we can bring my wheelbarrow, to carry your teeth," we see Ross reading the game manual at the end of the shot. At the beginning of the very next shot, he is suddenly rolling the dice with no manual in his hands. (00:17:00)
The One with the Blackout - S1-E7
Revealing mistake: When Phoebe says something like, "Look, the last candle is about to go out", she starts counting down, saying "-47,-48..." and you can see Monica looking at the candle. But there is a light source behind her (it can't be a candle because she is looking at the last candle). (00:20:05)
The One with the Blackout - S1-E7
Continuity mistake: After the light comes back on and Ross is holding his heart after he sees Rachel kissing Paulo, in the next shot when Joey starts speaking to him his hand is by his side. (00:20:40)
The One with the Blackout - S1-E7
Continuity mistake: At the end of the episode, as Chandler turns to the security camera, he is stood right next to the door. In the next shot he has jumped about 2 feet away from the door instantly. (00:21:20)
The One with the Blackout - S1-E7
Continuity mistake: At the end of the episode when Chandler watches Jill leave the bank, his face is pressed up against the centre of the glass door. In the next shot his face is leaning on the metal edge around the glass. (00:21:20)
The One with the Blackout - S1-E7
Audio problem: When Phoebe is counting down to the last candle burning out you can see Joey blowing out the candle, but the sound of his blow is only heard a second later after he sits back. (00:22:50)