"Thank you for having done this."
"No problem!"
"Obviously. Why would there be a problem?"
"..."
"Are *you* planning to cause problems?"
"No!"
"Then, why did you say 'no problem' when it was *obvious* that there wouldn't be a problem?"
"To signify that it wasn't a problem."
"Yes, but only someone who wants to divert attention away from problems would claim that it isn't."
"Er..."