OUCH! Thanks goodness for the jeans.
Many years ago, a few buddies and I built a go-cart with a 3hp B&S. It was pretty quick and it was the coolest thing on our block. Anyway, it was meant for only one passanger, but a second person could sit on a roll bar on the back pretty easily...just a PITA to balance. I was on the back this one particular time and a friend was at the wheel; he thought it would be a good idea to put it through some slolom turns and I went off the back. Only problem, my foot was stuck and I was being dragged on my knees on a freshly Oil and Stone street(If you've ever seen an oil and stone road, you could imagine). After the ordel, when we came to a stop, I looked down and to my amazement, I completetely removed the skin from my knees and was staring at my freshly ground down kneecaps; down to the marrow. Very painful...I still have the flatspots on my knees to this day.
So, It's a damn good thing for your jeans!