When Kate and John first meet Esther and speak to her while she paints lion cubs, her painting progresses a lot quicker than it should for the amount of time that passes on screen. Also in some of the close up painting shots, it's obvious from the fingernails that someone else's hand was used for those shots.
When Kate is shopping in the grocery store with Esther and Max , Sister Abigail calls Kate on her cell phone. As the camera cuts between Esther and Kate, the produce display changes without the cart moving.
When Kate climbs out of the ice hole in the pond, she is wet and her hair is wet when she picks up Max. But when there is a close up of her kissing Max, Kate's hair is dry. Her hair is wet again in the next distance shot.
When Kate is talking to Grandma Barbara in the kitchen about her drinking problem, she starts to eat a bit of the cake on a plate by the sink with a fork. However, every time you see the cake as the scene progresses, the amount of it left and the positioning of it is different.
Early in the film, at one point, the family returns home and it is snowing lightly. The windshield wipers stop and there is a brief overhead shot of Kate near the car with a lot of snow collected on the windshield. Not enough time had passed to allow that much snow to collect on the car.
When Kate slams on the brakes just before crashing into the house, the pedals shown are not those of her Saab 900. However, they are a match for the pedals in Sister Abigail's Plymouth Satellite.
After Kate enters "antisocial personality disorder" into an Internet search on her computer, as reflected in her glasses lenses, the screen immediately directs to a synopsis page clearly labeled with a different personality disorder, Borderline Personality Disorder. The two disorders are not synonymous.
When John opens the fish tank and sees the images on the wall the light goes across all the walls, however the light is not strong enough to give off that much light.
Early in the film Kate is startled when she closes a mirrored, sliding cabinet door and sees John standing behind her and to the right. Kate is facing the mirror more or less straight on whereas the camera is on an angle relative to the mirror. She should have been able to see John before closing the cabinet door.
(at around 1h 55 mins) In the credits the word "Russia" in Russian from Esther's papers is spelled wrong. The first letter should look like the Latin character "P," not "R" as was shown in the film. Cyrill P is Latin R. CPPP = S.R.R.R.
As Kate is racing home in the SAAB, when she passes under a street lamp it is clearly shown that the automatic gear stick is in park.
When Daniel is playing Guitar Hero on his Xbox 360 console, his controller power light is not on, indicating the controller is not on/or plugged in to the console. Also, when the game is shown on the television Daniel is playing on the 'Expert' difficulty and appears to be doing quite well, however looking at his fingers, Daniel is only pushing the first three buttons on the guitar (easy mode) and not all five buttons as Expert mode requires.
When Esther catches John and Kate having sex in the kitchen, the reflection of the couple in the glass shows John holding Kate against the counter with one arm. In the same shot Johns arm is not holding her down. Also, as John turns his head away from the glass, his face can still be seen in his reflection. The reflection appears to have been added in post production.
When Sister Abigail swerves to avoid hitting Max, the car's suspension does not react.
When a bystander is chasing the runaway Lexus, the steering wheel is about 1/4 turn to the right, making it impossible to roll freely down the hill in a straight line.
Near the end of the film, when Max knocks over the planter in the greenhouse, the crash is heard after it lands.
In the beginning of the film, when Kate is playing the piano, she is clearly in the key of C major, obvious by the fact that she is only playing the white keys of the piano. However, the music that can be heard is in the key of C# major.
When Esther is introduced to her new class, she is holding a Nelson Spelling book. These books are not used in the United States, where the film is set; they are, however, used in Canada, where filming took place.