Me: Sam, take this bag of school supplies upstairs and put it away.
Sam: Do I have to do it now?
Sam: Can't I just set it on the stairs for later when I go up there.
One minute later...I see the bag on the stairs and the lights on upstairs.
Me: Sam...are you upstairs?
Me: You mean you went upstairs and left this bag of stuff here ON the stairs?
Sam: I'm sorry...you SAID I could do it later.