I know that I have hesitated to move forward with good ideas because I felt I didn't have things worked out quite yet. I also know that I have stopped short of sharing new ideas or skills because I didn't think I knew enough to share yet.
My students sometimes hesitate to finish a phrase because they think it's not (or isn't going to turn out) good enough. They will stop and restart, only to stop and restart again in the same exact place.
Is it that they know they have a lack of knowledge or ability that makes them do this? Or, is it fear? Fear of being seen and heard "in progress."
It's almost always fear. A self-protect mechanism that somehow makes them feel confident that they can predict how badly, how unfortunately the future will turn out if they keep playing.
Professionals do it all the time - not sharing something we wrote, or a recording that will life a long internet life that is just not quite up to our standard.
How many things have you started and not finished because you're just not good enough, yet?
One of my favorite things to remind my students when they stop before they can make a mistake or as soon as something doesn't quite please them is that "gross is good." Gross means you are trying. Gross means you took a risk (you could replace the word "gross" with "mistakes"). Gross is human.
I don't know anyone who is perfect - as a person, or a musician, or in any other profession. We are all constantly learning, and we can actively choose our attitude by limiting ourselves and not trying, or trying and growing. But, if you never try you will never grow.
If you never let it be gross, it will never be good.
No one but you expects you to be perfect - they are too busy placing the same expectations on themselves.
What we all need to do is remember that we are the only ones who remember each event in our lives - the only ones who remember every single wrong note, every nervous moment - and that it is always more important to grow.
If you gave your best possible performance of a piece today and then performed the same piece in five years, they would be very different performances. Hopefully you would do it better - wouldn't you hate to be stagnant or move backwards?
But knowing you will be better in five years is no reason to avoid giving your best now.
Do what you can with what you have and you will grow.