I think that believing in something is a very interesting concept. Beliefs make us who we are, they control pretty much every aspect of our lives. Numerous people have died because of their beliefs. Whatever we believe to be is true, as far as we are concerned, is true. Even though there maybe substantial evidence to refute us, we still believe it. Think about how strong of a tool that is if used properly. I remember thinking at times that I cannot do something. I also have thought, it will be impossible to get the results I want out of this situation. Are these not merely beliefs? Why must we as people continually think the worst is going to happen and believe it. Whatever we think about inevitably comes to pass, not by magic but because we are thinking about it.
In my opinion, there is such fine line between being really good at something versus not so good. This may sound really silly but you see people who are really good at something believe they are good at it. On the other hand people who are not so good at something believe they are not good at it. No matter how you slice it, belief is the main determing aspect of being good at something. It does not matter how much practice you put into being good or how many hours you have worked. You have to believe before first!
The point I am trying to make is, lots of times we are so hard on ourselves. We critique our performance and find ourselves lacking. Our thoughts become reality. In general, we have the skills and know how to accomplish anything we wanted or the ability to learn, if we just believed this were true.