I think that many people are afraid of failing. Who ever started out being able to do something right the very first time? You learned to roll over, crawl, walk and then run. It takes time. Why do so many people feel they need to be "experts" at something the first time they try it?
I think many people live lives that are boring and predictable because they are afraid to venture out into something new, it's like a prison. I know people who won't go out dancing because they "can't dance". I hate to burst your bubble, but it's the people who CAN dance that we are all looking at!
I think people tend to forget that each day could be their last, most of us won't win the lottery (heck, I don't even buy tickets, so I definitely won't be winning!); it's unfortunate that fears hold some people back from experiencing thrilling events that can enrich their lives for the remainder of their years.
Think about your fears. Think about your satisfaction with your life. If throwing caution to the wind might make things just a little more thrilling.....stop letting fear hold you back.