I got all my tests back from the doctor.
He said, “They’re all negative.”
I said, “Shit.”
“No, no, no,” he said, “They’re negative in a positive way.”
“Oh,” I said. “So what’s positive?” ...
“Ah,” he said, “That would be negative.”
I looked out the window for a while. He twiddled with a pencil.
“Got anything for a headache?” I asked.
“How long’s the headache been going on for?” 
“About 30 seconds,” I said.