Mountain Bike Crashes
If you do it, you will crash. It's as axiomatic as the void needing filled. There are some fun ones, some crappy ones and some downright debilitating ones. Hopefully you get to hop on the bike afterwards and go. All of them make you hesitate and consider the speed you are going, the terrain, the bumps, the dips, the turns and soft shoulders; and this eats at you. Your object is to push it to the side and risk the next big crash.