On a PU truck or SUV this matters little. But the driver of a low-slung vehicle like our Spiders has to watch for particularly high sections or for those that follow a suspension-compressing dip for fear of the road contacting the car's bottom.
This happened to me once yesterday, with an unpleasant sound -- that of the bottom of the exhaust system's resonator being not to gently scraped on the alligator's back. Still, no immediate problems manifested themselves and we went on our way until stopping some miles up the road at a country store for some much needed refreshment.
After pulling out of the little store's small parking area onto the narrow winding road that is NH Rt 123a, my wife and I started hearing sounds that portended trouble. Metallic bangs and rattles. Sometimes they were loud enough to be startling, other times they'd almost disappear. These had to be identified! But on a tightly curving road with little shoulder finding a safe place to stop took some time -- time spent nervously listening to that terrible sound. "OMG! What is wrong?" thought I. My wife's expression showed that she was having similar thoughts.
Finally, after a couple of miles of such nervousness, the road briefly straightened and I saw a safe place to stop, put on my signal to alert my buddy behind me in his Miata, and pulled off the road, my buddy doing the same right behind me.
I looked over my shoulder as I got ready to open the car's door and exit, truly fearing what I'd find when I'd peered at my beloved Spider's belly. Then all of a sudden the crashing a banging sound started again, only this time much louder.
"How could this be?" I wondered, the car fully stopped and the motor off. Then the answer became obvious and I burst out laughing as from around the curve we had just passed came a pickup truck pulling a loudly crashing and banging trailer full of old tires and assorted junk.
Turns out my Miata driving friend was also looking for a place to stop. He thought it was his car making all that noise!
We laughed together, took the opportunity to take some photos of our lovely little cars, and then went on our merry and untroubled way.

That ever happen to you?
-don