Continuity mistake: As Wynona Rider is reading the diary, her hair changes. The hair is parted on one side and then it switches to the other.
Continuity mistake: In the scene when Deeds is delivering pizzas while walking down the street with Anderson and Chuck, the last pizza he delivers to "Crazy Eyes" obviously is a large, but apparently changes to a small when Deeds slides it to him through the jail bars.
Continuity mistake: When Deeds and Chuck Cedar are playing tennis, the guy who handed Chuck a tennis ball keeps switching from one side of the net to the other, between different shots.
Audio problem: We establish that the manor Deeds stays at makes an echo when you shout or yell. Yet when Deeds slides down the banister and crashes into the table, his very loud yelling and the smashing into the table never produces an echo.
Factual error: When we see Deed's Uncle being lifted off the summit of Mount Everest, you see him holding onto a very spiky and rocky summit. The summit is not like this at all. It is, in fact a much rounder shape, and not rocky. It is permanently covered in snow, therefore being something your body can get around and hold onto. (00:02:05)
Factual error: At the start of the film, when they are all climbing Everest, they are all seen without ski goggles. Without these, they would go snow-blind. This is only temporary blindness, but the climbers would have been more sensible than to not wear goggles, wouldn't they? (00:01:10)
Continuity mistake: When Deeds is in the pizza place before he finds out about his inheritance, Murph is standing there with him holding a blue Pepsi cup. It switches to Deeds then when it is back on Murph, he is holding a beer mug and he continues to hold this throughout the scene.
Continuity mistake: The cats falling from the burning building change color from the time the hit the trampoline to when they reach their final destination.
Continuity mistake: Deeds hands Crazy Eyes the french fries and Oreo pizza in the box. The shot cuts to Cedar and Cecil for two seconds but when the shot cuts back to Crazy Eyes, the slice of pizza is already in his hand. No way could he have opened the box, took out the slice and have it in his hands in just two seconds. (00:11:45)