I was sitting in my car minding my own business, with the AC on, reading a newspaper. A rap on the window startled me and I looked up to see an old man making the "roll down your window" sign. Since I was in a public parking lot I didn't think much of it, so I rolled my window down.
He said, "You need to keep your window rolled down." I just stared back at him, trying to figure out what made him in charge of windows in this particular parking lot and, yes, why he could possibly care. "Carbon monoxide," he said. "It's odorless, tasteless and invisible and when your car is running it can come up through your floorboards and kill you. So you need to open your windows if you're going to sit out here with your car running."
I couldn't think of what to say so I said, "Okay, thanks." When he walked away I rolled up my window. Then I thought, Really? Am I at risk when I am at a stop light, then? I should have asked him.
I wondered if I should be worried about dying every time I sat in the car with the windows up and AC on. But then I started thinking about his description of carbon monoxide: odorless, tasteless, invisible, deadly. I suddenly realized he wasn't talking about carbon monoxidea at all... he was talking about iocane powder! Fortunately, I've spent the last several years building up an immunity to iocane poisoning.
Take that, old man!