Factual error: In the scene when Deeds rescues the woman from the fire, right before him and her jump out the window, all seven cats were rescued, but we can visually see a black cat on the left of the screen on top of the stove. Deeds and the woman jump from the window, leaving the black cat on top of the stove to burn in the fire. All seven cats were obviously not rescued.
Factual error: At the start of the film, in the shots with Mount Everest, climbers aren't clipped onto fixed ropes. On all the biggest peaks on the planet, climbers will always used ropes fixed onto the mountain, and because they are attached to it, it can stop a fall. But in Mr. Deeds, this doesn't happen.
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.