Goofs

When the family first arrives at the new house, there is a car in the driveway. As they move to the steps and side of the house, the car is gone.

Nick hands Lindsey a $10 bill for lunch, then pulls it back. The bill is folded in half with the 10 at the top. The bill flips around in Nick's hand even though he doesn't move it.

When the Pearsons new neighbor talks to Nick about Chuck's wife he had glasses on, when they focus on Nick and back at him his glasses are gone, they don't show him taking them off, and so quickly, not possible.

An ultrasound at her stage of pregnancy would not be so clear, it would just look like little peanuts, not babies.

Kevin picks up a pneumatic nail gun and fires off several nails towards the ceiling simply by pointing the nail gun straight up and pulling the trigger. A pneumatic nail gun requires the tip to be pushed onto the surface you are nailing, acting as a safety, before it will fire. This prevents just pointing and shooting, like Kevin does.

The unlicensed electrician tells Nick to not use the toaster and microwave at the same time, which the movie uses to justify his inexperience. Actually, this is common sense and a licensed electrician (and any licensed contractor) would agree, which ruins the joke.