When Harvard Hottie is reading the letter from Mrs. X at the end of the movie, the words he says do not match the words on the letter. The opening line reads, "It's been sometime since we have spoken," and Harvard Hottie says, "It's been several months since we have spoken."
When Annie returns to the apartment after being fired, she takes a swig from the liquor bottle before even looking for the "Nanny Cam." But when the mothers are viewing the tape later, we see her take the same swig and then immediately begin speaking to the camera.
When Annie takes Grayer to the play date at the house where
he and another boy are decorating a cake, a glob of the pink icing lands on the front of Annie's white t-shirt. In the next scene Annie is at Lynette's apartment. There is pink icing stains on Annie's white t-shirt but not the one from the previous scene.
When Annie is taking Grayer to the Museum of Natural History, they are shown running across Central Park, then taking the S train, and then coming out of the B and C train stop next to the Museum. However, there is no S train in this part of Manhattan.
In line with the desire for the child to learn French, his birthday cake is iced with "Happy Birthday" written in French. However, the cake said "Bonne fête," which is Quebec French, instead of the more suitable "Joyeux anniversaire" or "Bon anniversaire" used in France.
While drinking with Lynette in a hotel, Annie says that Mrs. X (her employer) dumps all of her problems with her husband onto Annie. Lynette replies that it's denial. "Denial" is one of the psychological defense mechanisms proposed by Freud whereby a person refuses to accept a reality. Here Mrs. X's behavior is not denial, instead it is another defense mechanism called "displacement".
The goof item below may give away important plot points.
When Annie is on the boat back to the apartment after being sacked there is a close-up shot of the puppy and her suitcase with her payment envelope poking out. However in the next shot when Annie goes to pull out the envelope only a small section is in the suitcase and the majority of it is sticking out.