I had an accident 30 years past when I was really numb to being a more causes rider. I was running too fast around a winding lake road, and was about to head uphill to my left, I was on the crown of the hard, near 90deg left turn, when my front tire hit the only rock in the center of the road.
That small 2" rock caused my bike to slip over the crown and I was thus sent slidding at 60+mph, down into the curbing. When my front wheel hit, I was catapolted into a 6" concrete encased stell berrier and then flipped wildly up into the air and out into the path of another car. I bounced off the car and then back onto the small turf patch between the conversion of the two directional lanes.
The impact of hitting the pole, split my helmet and fractured my face, it was a full faced racing helmet and was splintered into pulp. The impact of the car and being sent back over to the turf patch impacted my back as well. I spent several months recovering from reconstruction surgery of my face and back.
Needless to say, I always ware a helmet on any motor bike I ride. I still ride my big bikes today and have a bit more caution to uphill swinging curves.