Suckerfish on the Side of Your Whale

Me: "Is there anything in the box where it says 'Open'?"
User: "Yes."
Me: "What is in that box?"
User: "Nothing."
Me: "OK... I'm referring to the box immediately to the right of the word 'Open'. Is there anything in there?"
User: "Yes."
Me: "Alright. So what is in that box?"
User: "Nothing."
Me: "... See, there's either something in this box or there isn't. Is there anything in the box?"
User: "Nope."
Me: "OK then."

Argh.