Fear of Failure perhaps?

History has shown how we grow from the harvest of good ideas. We benefit from the success of other people's ideas. But, we also benefit from our failures. Great experience comes from bad experience. We can and have learned from our mistakes.

So I guess my point is..... is that yes, we cannot always know if an idea will turn out to be good or bad. If it turns out good.. then great! If the idea does not prove to work as expected... well thats ok also. What is important is that we have learned something in this process. And we can try again.