WARNING: Toy Story 3 spoiler alert
While watching Toy Story 3 tonight with the kids, one of the toys says, "what a nice bear." My four year old piped up and said, "He's not a nice bear. He's just pretending to be a nice bear, but he's a monster inside."
Holy smoke, I did not expect that sort of insight from my son. Actually, he was quoting a line from later in the movie (as my best friend kindly pointed out), but still...it's amazing what a child can understand about humanity and sin nature.