There are three possibilities:
You are either good, trying to get good, or you’ve given up.
If you place yourself in the first and are convinced that you’ve learned and mastered it all, or even just one domain, then you have already proven your ignorance.
If you are in last, then you are in a wonderful position to take chances and try new things.
Most of us fall in the middle, driven by the first, afraid of the last, and that’s what keeps the balance.