Live Alone and Like It (a.k.a. An Unexpected Song) - S1-E19
Continuity mistake: Lynette opens the door while she has sunglasses on. Then she is holding her glasses. It never showed her taking off her sunglasses. (00:13:20)
Visible crew/equipment: When Susan sits on the couch in Edie's house, just after she throws the bra behind her and knocks the candles over, a crew member in blue jeans can be seen moving on the floor behind the couch to the right.
Continuity mistake: During the scene where Gaby and John are in her bedroom talking, she takes a drag from her cigarette while John asks why she isn't happy, but never exhales the smoke from that drag. 23 seconds pass from that drag to the next one and she's in frame the entire time (it cuts between shots of the two of them together and Gaby's close-ups, but doesn't cut away from her). It's also worth noting that Gaby is never seen smoking again at any other point in the series and no explanation is given as to why.
Audio problem: As Carlos is giving his speech at the barbecue, Julie sees Zach and says to Susan "Oh God". After cutting to a shot of Zach and his father it shows Julie and Susan again. If you look to the right of the shot you will see Carlos' face is just looking in front of him and not speaking, but you can still hear him giving his speech whilst he is in shot.
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Continuity mistake: When Bree Van De Kamp is sitting on the couch talking to her marriage counselor, as she is doing so she picks up her purse and puts it on her lap, crossing her hands over it. When the camera switches back to her a second later the purse is back on the couch beside her in the exact position it was in before she picked it up.
Plot hole: Rex is in the hospital for having a minor heart attack and is awaiting surgery to receive a pacemaker. 1) He isn't connected to an ECG or any other heart monitor so no one is aware of his heart attack. 2) They ran blood tests and checked his potassium levels. They would have also checked the concentration of his medication in his blood. (This should have been done earlier in the season too when they first discovered his medications were not working.) Zero concentration of medication in his blood could throw suspicions on his wife just as easily intentionally giving him potassium.
Continuity mistake: When Lynette is feeding her baby, we see from behind there is a backpack on her chair then when the shot changes it is not there. (00:29:55)
Continuity mistake: When Lynette comes out of the pool, after getting her boys, she is wearing high heels, but when the shot changes to a distance, she isn't wearing anything on her feet. (00:13:15)
Audio problem: When Susan suspects someone might be in the house, the seduction music she has put on for Mike is drowned out by the score. When she accidentally hits Mike across the face, the score stops, but the music that was playing in the background has gone. The song in the background before now was music within the show, and it was loud enough to be heard around the house, so we should still be able to hear it.
Continuity mistake: When Gabrielle and Carlos are saying hello to Ashley, the position of her hands change on the ball, from the front to the side to the front again. (00:14:40)
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Factual error: Lynette's neighbor tells her that the pot Lynette's sons gave her is really hers, the neighbor's, and she bought it in Costa Rica. She turns the pot over to show Lynette that the price is marked on the bottom, with a number followed by the letter p. One supposes that the p might stand for peso, except that the currency of Costa Rica is the colon, which consists of 100 centavos. No p in sight.
Continuity mistake: When Bree goes to see Zak, in one shot her hands are intercrossed, then in the next her arms are crossed. (00:17:55)
Continuity mistake: When Lynette and Gabrielle are talking to Paul, the boxes Gabrielle are holding change position between shots under her arms. (00:34:30)
Continuity mistake: When Bree Van De Kamp is first shown with her muffins, we see that the hand towel on the right basket is not in her hand, then when the shot changes it is. (00:05:20)
Continuity mistake: When we see Lynette driving her kids, in the first shot we see some red, blue and white decoration in the front of the car to the right, then when the shot changes it's in the centre. (00:13:50)
Running to Stand Still - S1-E6
Visible crew/equipment: When Susan is following Paul in the car she borrowed, we can see the reflection of a crew member on the right hand side of the window. (00:18:15)
Continuity mistake: When Mike comes home with the shopping bag, we see that the items in his shopping bag change positions in between the shots when he goes to see Edie arrive. (00:20:30)
Continuity mistake: When Julie is leaving we see that she leaves the door open and then it closes with a slight open gap, yet just for one shot the door is completely closed, then it's open again. (00:09:50)
Continuity mistake: When Lynette is in the supermarket, right after she loses track of the twins, she is seen pushing her shopping cart down the aisle,and in the seat there's only a pink blanket. But when she sees Nelly Klein, her baby daughter is sitting in the seat with the blanket and one of her sons is riding in the basket.
Chosen answer: Poker. They have been playing that this whole time, once a week with everyone who was invited that lived on the Lane.