Having hit my head after falling in a parking lot you'll never catch me riding without a helmet.
Long story short, I was running through a parking lot, fell (thanks Brian for shoving me), and hit the back of my head. So, I was moving about 10 mph. I was knocked silly and don't remember much of the rest of that evening although I do remember my buddy trying to get me to go to the hospital and I wouldn't. Got up the next morning and felt like warmed over death. Took a look at myself in the bathroom mirror and both of my eyes looked like Mike Tyson had done a number on me. They were completely black and not blue.
I hauled my ass to the hospital and found out I had a small fracture in my skull, some bleeding in my brain, and both of my ears were full of blood behind the ear drums (this explained why I couldn't hear very well). The black eyes came from my brain slamming against the back of skull and then bouncing back which broke blood vessels around my eyes. I spent the night there under observation and missed 2 weeks of work after that. Hell, I needed a wheelchair ride out because I didn't know the way out nor could I walk that well.
All of this because I fell in a parking lot. You will never catch me riding without a helmet. I have heard all the arguments for not wearing one and frankly it just makes me mad to listen to them.
My mishap was minor compared to the sad story in the linked video. Somebody lost their life because they didn't wear the gear. I'm just trying to illustrate through my own experience how easy it is to injure your head and hopefully convince any of you helmet naysayers to wear that helmet at a minimum!
Steve
