About 20 years ago, my wife and I were on a somewhat longish drive in western Massachusetts, at night. I started to hear an odd, troubling, knocking sound coming from the passenger side of the car. I asked my wife if she heard a strange noise, and she said that she did. I pulled into a parking lot and walked around the car, looking carefully for whatever was wrong. I looked under the car. I found nothing, and so we pulled back onto the road. The noise began again. I became worried again. I wasn't sure what to do.
At some point I said to my wife that I was afraid that a tire on the passenger side might just detach and roll away, or something like that. She said, ``Passenger side? The noise is coming from the driver's side.'' Immediately I opened the lid of the small storage compartment between the front seats, and we were both able to see that there was a full, unopened can of soda, bought at the previous rest stop, rolling back and forth, causing the knocking sound.
I suppose there's no real point to this story, except that occasionally our worries really are unfounded.
