When my niece was about 4, we visited the nextdoor neighbors one day. She & the neighbor kid were playing in the living room when they had a disagreement about something. So the neighbor kid stomped off to his bedroom & closed the door, apparently to get away from my niece. She tried to continue playing in the living room by herself for a while, but it just wasn't as much fun as it was with a playmate. So she marches up to the bedroom door & yells at the kid "You better not be playing with yourself in there!" Obviously she had no idea how that sounded, she was only 4 after all; but me & my buddy (the other kids dad) just about spit our beer out laughing over that.