Discussing the finer points of armor classes, cloth, chain mail, plate, etc...with a 4 year old wearing a steel bowl on his head as I bounce things off of his head, literally and figuratively.
I pretend to throw a big mayo jar at his head. The following occurs:
Him: "Why didn't you throw the jar at my head?"
Me: "Because armor just helps you avoid getting hurt by some things."
Him: "So it would hurt?"
Me: "Yeah, armor doesn't make you invincible"
Him: "Are scientists still working on that?"
Me: "Yeah buddy, they sure are."