I used to bike furiously in the summer heat. Mesmerized by the glint of hot pavement and babes. I was fit. I was fast. I was aggressive. I was imprudent. I thought everyone should get a good look at my ass, even if I wouldn't let them touch it. I did not wear a helmet.
One day I was biking down Jarry blvd on my way home from my dreary job. I was 3 klicks into a 32 klick journey home. Some creeper opened his car door without looking. I saw him just in time (or so I thought). Being acutely aware of my environment, I knew there was no car to my left, so I weaved. The tip of my right handlebar caught the edge of his door, and I was certainly doing 30 kph on a light downhill slope. I was thrown from my bike into the lane to my left, and whacked the back of my head, scraping my elbow and knee.
Like a cartoon, I saw stars, and before my vision came back with any clarity, I rolled over to the right. A 10-wheeler rolled over where I was less than a second later - no way it could have stopped. I was lucky - the hit I took could just as well have knocked me unconscious, and if that had happened for even a second, I would have been dead.
It took me 45 mins until I stopped shaking, and could deal with the pain enough to bike home, a little slower and cautiously than before.
Being young, invincible, and too cool to wear a helmet, I told everybody about it with some alarm, and kept behaving as I always did. You know, because it was the other guy's fault - he was the creeper, not me. I had to age a little before understanding that his life was never really on the line.
Looking back on it now, I would estimate that I suffered a little brain damage, which explains why I am in the RIA today.