Fear is what limits some people from advancing in life to greater heights, fear is what makes a lot of dreams never come through, we have to build up our courage and be more determined for excellence by having confidence in ourselves, not having more about this courage needed is a big challenge on its own, because we are going to be limited on what we can do in life and how far we can go.
Generally, people fail to face their fear and conquer it so they comfortably live with the challenge unsolved. Life is filled with different threats that deserves thorough approach and consistent resilient to solving it. However, not everybody has the guts to do that, and as you said courage to confront certain repetitive problems. For instance, they are sellers who can't boldly convince prospects to purchase a product, instead of going for sales conferences to build confidence they'll blame it on their inabilities to speak properly or use the right wordings. Then the trouble defeats them and they continue to perform poorly in selling.