Dishing it out, taking it

Yesterday, Wild Thing surveyed the disgraceful state of my workspace. Here may be observed random piles of paper, scattered books and bookmarks, and the occasional used tissue from last week's cold.

WT: "Daddy, you made a big mess."

Me: "Yes, WT, you're right. I should really get this cleaned up."

WT (looking at me very seriously as he echoes back a phrase now familiar to him): "Now, what did you do that was not OK?"