My son (10) and I were walking down Main Street when we passed a woman bent down in her son's (probably 4) face. After we passed her my son & I looked at each other and he said, "Mom, was she about to bite him in the face?" That's exactly what it looked like she was going to do. Now whenever we get crabby with each other at WDW we'll quietly say, "Don't make me bite you in the face" which always makes us laugh and stop being crabby
Not in a park but Disney related - My second day of Peds clinical for nursing school I was in the room of a 6 year old who wasn't coping very well. I was trying to talk to her to get her mind on something else, and we ended up trying to name the 7 dwarfs. I had named Grumpy, Sleepy, and Dopey when as seriously as she can, she says Stumpy. I thought maybe she was confused, so I said we already said Grumpy. She said, "Noooo, Stumpy. There's Grumpy and Stumpy."

My son and I are now always on the lookout at WDW for Stumpy the elusive eighth dwarf.