Most people are often scared to fail because they don't want to accept the fact that they may or may not be good at something they really want. So many people have big dreams in their life and some have spent their life dedicating it to something. And failing can bring someone to such a low level in their life, that they no longer have any motivation left. Failure can lead someone to think they aren't good enough, they don't try hard enough, and just doubt themselves. Which can make failure scary because of the emotions they feel after.