Used to wear a helmet 99% of the time. On one of those 1% rides, it was a cool evening ride around a small lake. I was going a little to fast. I'd been around that curve many times 40 or 45 mph, but somebody in nearby gravel parking had lot had spun the wheels on their car throwing gravel on the curve. I hit it while doing 45 to 50 mph when I hit gravel and laid down the bike. I would have just skinned the bike and me but the front wheel hit one of those wooden ballard post (ballards to keep cars off grass and in gravel parking lot). The front wheel hit the ballard, my forehead hit handle bar and the mirror ripped into forehear requiring 270 stitches. No permanent damage to my head, just an ugly scar. Now I wear my full face helmet 101% of the time. PS My crotch and legs totaled the gas tank. I was black and blue for weeks in places that shouldn't be black or blue.