Duh, Mom!

Henry~Oh NOOOO, Mom. We forgot to go ride a horse today.
Me~ Were we suppose to ride a horse today?
Henry~YES!
Me~Hmmm, ok I didn't know that. Maybe another time.
Henry~Well if you bought me a cowboy costume I would need to ride a horse. Don't you know that?
Me~I didn't know that.
Henry~Why I gotta tell you these things.