Plot hole: In this episode Carrie runs into Aidan, who now has what looks to be about a 6 month old baby (Tate). This doesn't seem possible, as Carrie and Aidan would have only broken up about a year ago, and Miranda was around 6 months pregnant when they broke up. Brady is only about 5 months old at this point in the series, leaving Aidan only roughly 8 months to have this baby - but Aidan lay in bed for about a month and then dated Nina Katz for awhile. Timeline just doesn't seem to fit.
Continuity mistake: When Carrie is telling Alex about her Parisian fans and the party she's been invited to, her cigarette pack not only changes position in her hand with her coffee cup, but also disappears and reappears several times.
Plot hole: When Carrie runs into Aiden on the street, he tells her that he 'married another furniture designer'. Although Carrie is happy for him, it doesn't seem likely that she wouldn't have known about this. Steve and Aiden are business partners and close friends, and Miranda is very close to Steve with their baby. Carrie would have undoubtedly heard about Aiden's marriage through the 'friends grapevine' before that, as news that big wouldn't just slip under the radar. Someone would have told her, so it isn't logical that she is just now finding out about Aiden's marriage.
Continuity mistake: At the end of the show, when Carrie visits Jeremy at the psychiatric facility, they are sitting outside having a picnic. As they are talking, notice Carrie's necklace. It is a bolero-type necklace and the red stones on the end move up the necklace to near the clasp and then back down into her cleavage. Then they go back up again.
Other mistake: When the plastic surgeon is giving Samantha a breast exam, you can tell that he isn't really examining her breast. He is actually moving his hand in a circular motion in the air above her breast pretending to give her an exam, but is touching her hospital gown instead.
Continuity mistake: In this episode, Brady has the Chicken Pox. But when Robert visits Miranda at home and picks up Brady, there is absolutely no sign at all that he has Chicken Pox. It takes awhile to get over Chicken Pox, and for them to fade. So even if Brady is recovering from having Chicken Pox recently, he would still show signs of it. It couldn't go away that fast, and it's way too soon for Brady to be completely clear.
Character mistake: When Charlotte is looking at her wedding announcement in the New York Times, there is a close-up shot of part of the article. It says, in reference to Charlotte: "She is a writer and editor at Fashions Magazine in Manhattan". This is not true, nor has it ever been true. Perhaps the producers of the show threw that in, to see if anyone would notice. Also, the same article mentions: "The bride, who will be keeping her name..." and yet we never really hear Charlotte use the name York instead of Goldenblatt.
Continuity mistake: When Carrie has left the dessert place and is walking in the street; just before she sees the small child, there are two extras (male and female) behind her using a single umbrella. After the small child hits Carrie on the head, you can see the same two extras behind her without an umbrella. When the small child sticks out her tongue at Carrie, you can again see the two extras right behind Carrie, still not using an umbrella. When Carrie looks back again, just before stepping in dog poo, suddenly the two extras are completely gone, and the street is almost empty. Then when Carrie does step in the dog poo, the two extras are seen again farther back, again using the umbrella. In the next shot, a close-up of Carrie, the two extras are right behind her again, and passing her, without using an umbrella. At this point Carrie speaks to an older man coming from in front of her, and the two extras have completely disappeared from the street again, even though they have just passed her. This entire sequence took place in a very short period of time, and was obviously edited together.
Continuity mistake: After Carrie rents the car and takes it back, she and Miranda are sitting on the couch talking. As Carrie says something, she turns her head to the right, looking straight at Miranda. When Miranda replies, "Well, that's one option", you can still see Carrie's head in the shot, turned towards Miranda on the right. But then in the next shot of Carrie, she is facing straight ahead and talking in the middle of a sentence.
Continuity mistake: When Miranda is running in the streets looking for Mary, there is a close-up shot of her face. You can see that it's raining heavily, as the rain is apparent in the scene. But during the rest of that sequence, as she is out in the streets, there are no other signs of rain, or of people being affected by rain. There is just snow on the ground.