Gentle persistence can be a very effective practice when what you seek is just out of reach, carry on and you can succeed.  That is, the practice of firm continuance in a course of action in spite of difficulty or opposition.

There is a fine line between persistence and being stubborn or obstinate.   Hence the modifier, gentle persistence.  There can be great value continuing until you succeed or even just until it is clear you will never succeed.

Personal Satisfaction

Whether you achieve what you wanted knowing that you were fully committed  and everything you possibly was done, is worth more than getting the object of your desire.

Self confidence is not founded not on accomplishments themselves but rather the personal  belief you can and will do what is needed.  Simply put you will try and continue to do so until their is no reason to continue.

Not Failure

Having undertaken all possible approaches yet still not reaching the desired objective does not constitute failure.   Failure is always associated with giving up before you are done.

This is not intended to imply it is okay not to attain your goals.  Rather it is not okay to not make every reasonable effort and continue until you succeed.  Perhaps not surprisingly this actually  results in attaining what you seek or close to it most cases.

Feeling Good

Most importantly knowing you did not give up always leaves you with a feeling of satisfaction around a task well done.  After all you did everything you could.