When Annie receives the shower invitation it reads "Sat." as the day. When Annie's car breaks down on the day of the shower, and Ted picks her up, she asks him, "Were you busy?" and he answers, "Well, it is Friday."
At the shower, Annie furiously rips a portion of the cookie but in the next shot, the cookie is intact before she goes to punch it.
When Annie is asking Rhodes to help them find Lillian, when Rhodes is standing at her car door he has what looks like a couple days worth of stubble on his face, but when he is back in his squad car, he is clean-shaven.
After Annie leaves the bridal shower, she is seen driving down a two lane rural road. Megan, with numerous puppies in her van, pulls up next to and passes Annie. The street they are driving on suddenly has changed to a five lane highway with a more urban background. Megan pulls in front of Annie and speeds away. Seconds later, Annie slams on her brakes to avoid hitting a porcupine, and once again is on a two lane rural road.
In the dress shop, Annie's sweat spot on her dresses switches from big to small and back again.
Throughout the movie, Officer Rhodes' squad car has standard Wisconsin license plates. Police vehicles in Wisconsin have special issue plates.
(possibly intended) At the bridal shower, the waiter offers Annie a glass of champagne, saying 'It's French'. All champagne comes from the Champagne region of France. Anything originating elsewhere including elsewhere in France is called 'sparkling wine'. It is possible, though, that Helen's snobbery and wishes to impress had her tell the waiters to specify to the guests that the champagne did indeed come from France.
People don't have to be missing for 24hrs before the police will act - it depends on the person and the circumstances.
There is no partition between the front and back seats of the police car.
When Annie and Rhodes are on the side of the road with the radar, the radar is actually a Kustom Signals HR-12 model which is not wireless. The cord has been removed, meaning that what Annie is holding is a dead, non-working unit.
The Wilson Phillips CD Lillian gets as a present is a greatest hits compilation featuring the song "Hold On", rather than the original album this song appears on. It isn't the wrong CD, just a different one.
When Annie is hanging on the gate, a Jeep pulls up. The rear-view mirror of that vehicle has been removed.
The rear view mirror of Megan's minivan has been removed.
In the bridal shop, Helen asks Annie, "That gray didn't look a little lamb to you?" instead of the scripted line, which was, "That lamb didn't look a little gray to you?"
Annie gets pulled over for no tail lights and later is in an accident. The cop blames her lack of tail lights for her being rear-ended but brake lights work independently to tail lights.
When Annie receives the bridal shower invitation, Helen's voiceover says, "at the home of Helen Harris III..." The invitation reads, "at the house of Helen Harris III..."
An Orange County Transportation Authority (OCTA) public bus can be seen in a background shot. OCTA operates in Orange County, California. The film is set in Milwaukee, Wisconsin.
Officer Rhodes picks up Annie after the wedding in his police car & says he is on duty. He is a police officer in Milwaukee, WI. The wedding is in Illinois.
The overhead shot of Annie driving to Chicago for the engagement party, shows signs for Madison, Chicago and Green Bay. The car she's driving is headed toward Green Bay, which is north of Milwaukee, so she's in the wrong lane. Chicago is south of Milwaukee.
Twice throughout the film the Officer Rhodes says the names of intersecting streets in which characters live in Milwaukee, but when the location is shown, the street signs have different names on them.
No professional baker would bake a single cupcake in a pan without filling the empty cups with water. This gives even baking and prevents the pan from warping in the hot oven.
Rhodes is seen in a bar drinking alcohol while in uniform. Law enforcement officers never do this in uniform and if they did would be subject to extreme disciplinary procedures.
When Helen and Annie meet Helen's step children at the country club, Kristen Wiig can be seen mouthing "put another quarter in the swear jar."
When Annie and Rhodes are on the side of the road with the radar, Rhodes says for her to aim at the license plates of the cars, which gives the best reading. This is not true, as radar is a frequency that emits a cone that will respond to any moving object within range, and its range is infinite. Radar doesn't react to reflective license plates, but to moving objects.