About half way through the movie, Henry walks into the backyard with a drink in his hand which he spills to about 1/4 beverage left in the glass. In the next scene, while he is still in the backyard, his glass is now 3/4 full again.
In the scene in the backyard where Henry tries to catch the little girl, he falls. While lying on the ground, he takes a sip of his beverage which is almost empty. When he gets up, the drink is half full and a lime has appeared in it.
When Henry and Mrs. Wyatt are talking in the backyard about the lousy stucco job he tells her "it's REALLY just a waste of time", but when Millie is playing back the recording she made of them talking, Henry says "it's KINDA just a waste of time". This shows that Millie's recorded playback was not their original conversation but was prerecorded.
When Henry and Millie are having the water balloon fight in the back yard, the mother, Dawn, is wearing overalls. In the beginning and end, both of her shoulder straps are up, over her shoulders; but in the middle, there is one shot where her left shoulder strap is down.
Patience's glasses were extremely thick, indicating they had a lot of power in them, further evidenced by how little she could see without them; however, they displayed little to no magnification effect, which means they in fact had no or very little power.
When Patience (the cashier) looks around in the store and cannot see,she puts on her very thick (1 inch!) glasses on and then can see however, the thickness of the glasses somehow do not cause her eyes to look huge as they would in reality.