Here's my helmet story. I was once stupid, i.e. young, and back in the 70's pedaled without a helmet. My best friend and I were on a joy ride west of Washington, D.C. in 'horse country'. At the bottom of a steep, curving road, he went off the pavement slightly. Something caught his wheel and suddenly he was in front of me in mid-air completely upside down, still seated, gripping the handlebars and locked into his toe-clips. I can still picture it. He landed with his head about 12 inches from a fire hydrant which would surely have caused more damage than did the dirt he actually hit. A woman on a horse appeared from nowhere, asked if we were okay and then rode off back into the woods. The next day we both bought helmets and I've never once ridden without one. Those old 70's Bell helmets really built up your neck muscles. (This last statement makes this a vintage posting.)
The second day after I moved to Cleveland, a car pulled out of a parking space while I was tearing by, hit me and threw me onto my arm and the front of my helmet. I still have scars on my arm and the helmet, but not on my face. The car looked worse than I did, with a satisfyingly big dent in its front fender. We called it even.