Watching fail videos can be a very interactive experience. The reason I say this is, it is like you can almost feel the impacts in these videos. Often, whilst watching, it is hard not to let out an "OUCH" out loud and grab the respective part on your own body you see getting hurt in the video. While I know it can be somewhat cruel to laugh at other people's pain, at no point did I say you needed to laugh at any of this. I am simply pointing out that are worse ways to spend five minutes.
Keep in mind, in most instances these people were trying to flip over walls or mountain biking down extreme courses. It is not like these people just "failed" and got hurt in their living rooms. No, most of these cats were being "extreme", and if there is one thing I know about being "extreme", it often ends in broken bones.