Corrected entry: When the girls are walking down the street after eating, they all decide to go shopping downtown. Only Miranda says, "I forgot the Snuggly", implying that she can't go shopping with them. So Samantha rushes her off in a taxi. But in reality, this doesn't make sense. Miranda has already been out with Brady for hours, eating with the girls in a restaurant and then walking with him in NYC. So why would he suddenly need his 'Snuggly' to go shopping? If he was fine with all the activity before that, there is no reason he wouldn't have continued to be fine while shopping.
Corrected entry: When Carrie is talking to the cute guy while hiding out from the rain, she tells him, "I was engaged last year". But the previous episode, when Mr. Big moved to Napa, it was just becoming Fall in NYC. So it doesn't seem likely that only one episode later, it would be months later into the next calendar year.