Doing Our Best For Us

Doesn't matter what you do in life, or how well you do it, someone out there is always going to let you know that they can do it better. Regardless if they literally can, or if they are just tooting their own horn in hopes of tearing you down in order to build themselves up, you will always be told or shown that YOUR best wasn't anywhere near as good as THEIR best.   
So? Why does it matter? Why do we allow another's opinion, another's experience, another's competitive jealousies to dictate our worth, rate our accomplishments, and point out our failures?
We shouldn't!
If our best is what makes us happy and fulfilled, no one else, or their jealous and competitive natures, should ever be allowed to occupy a single space in our lives or our heads.
We should each do our best for us and our lives, and not ever for the approval and acceptance of others!