Possible? Impossible?

I have always wondered if it's really possible to overcome our limits. I have already written on this subject but, as usual, finding a "final answer" is not so easy. If I look at a certain result that I was not able to achieve to the extent I wanted, I have to admit that - in spite of my good will and effort - not everything is possible. On the other hand, if I think of a circus acrobat who is able to carry out unbelievable performances, I start doubting again: is it the outside world or is it me? The acrobat reaches outstandings results with great patience, commitment, sacrifice, trust. Most of all, he believes in himself, in his skill, in his capability to achieve the goal. He never gives us, he never loses sight of his target, he never loses faith in the goodness of his endeavor. He knows that his effort is worthwhile and that it will yield its fruit in due time. How do I feel about myself? How do you feel about yourself? How strong are we? How easily can we be disappointed, defeated by a failure? We often feel we are struggling against forces that are beyond our power. But this is not (always) true. We must keep riminding ourselves that "we can, if we believe we can" (Virgil).