Mental block. Why do we have them? Fear, anxiety, past failures, they can add up and therefore keep you from your best. No one is exempt including myself. But how do you deal with them, that's the question.
As a coach I can see potential in people, I have an idea of what they can do. I never think that they can't or won't accomplish. I focus on the good and the progress. If I ask you to do something on the track, I expect you to do it because I know You Can.
There will always be some risk and you must learn to face the challenge. Don't be afraid and if you are, let your faith be stronger. I put my rider on my bike with me to show him he could do it. Physically took him over the jump so that mentally he would know he could do it. After that, he got on his own bike and did it, it worked. I won't always be there to do that so you have to have faith yourself! Mine comes from above and it works like a charm for me. Believe and face your fear, you can with the right outlook. :)