See this face...
Me: upon noticing our son leaping from kitchen stool to kitchen stool, at risk of life and limb, "Jack, quit jumping on the furniture!"
Jack: "Huh? It's not furniture."
Me: "Quit. Jumping. On. The. Furniture."
Jack: (pounding said stool with fist) "It's hard, see. It's not furniture because it's hard. Furniture is comfy. This isn't."
Me: "It is furniture. And quit jumping on it. And while I'm explaining this, the table, chairs, and non-comfy objects are furniture."
Jack : (giant exasperated sigh) "Nope. They aren't. But I'll stop jumping."
Because he was like, doing us such a huge favor.