When I used to be into BMX's and Jump bikes, or just general skatepark riding I had myself a bad injury. 2004, at my local park, I was riding without a helmet and went up a small quarterpipe, didn't quite make it to the top and fell back down, hitting my head hard on the concrete floor. There wasn't a mark on my head. I went home and towards the evening my head began to ache (I can't remember any of this from this point on, just what my parents told me) so I went to sleep. Couple of hours later I couldn't sleep, the pain was just too much (apparently), and my parents came and checked on me, notcing that one of my eyes was looking in the other direction. They took me to a local hospital who thought it was just a virus that had nothing to do with my accident, they gave me a CAT scan and found I had a fractured skull and a blood clot had built up inside my head. Into the ambulance and speeding off to Great Ormond street hospital in London, where the clot was removed. Another hour and I would have been a goner, if I would have gone to hospital too early they would have found no symptoms and sent me home, off to bed never to awake. Lengthy story, but I'm very lucky and glad to be alive. It shows what can happen if helmet's aren't worn.