I remember being invincible when I was a teenager, apparently that trait was not passed on.
I was mountain biking with my high school age son a while back and we got lost and ended up on the black trail, which more properly should have been called the black and blue trail. We came to an amazingly steep downhill section, about 4 stories, steep enough that one could not possibly even stand, with a creek at the bottom and a short uphill bit. I wasn't concerned about the hill, all one has to do is stay upright and gravity will do the rest. I was concerned about how soft the mud was in the creek as I would be hitting that at about 50 mph, but seeing as I could not see any dead bodies, broken bikes, or even stray bike parts I figured it must be solid enough so I went for it, just a couple of grunts and I am up the other side. My 16 year old, should be invincible son is sliding down the hill gingerly on his butt. He then splashes through the creek and walks up the other side. He get to me and says "I am not proud of what I just did but I am glad that I did that."