The correct answer to this open question is the following.
I pick the following. "Experience is the teacher of all things."
This quote is so true, that is why I like it.
You can read books and study many courses, but what really teaches you is experience.
Until you directly live a situation and you are forced to make your own decisions and take your own actions, that is when you really learn.
It is true that there is no better teacher than experience. Once you have lived something, you get the lesson. The more you live, the more experiences you have. And I am not talking only about longevity, which is obvious. I am talking about living, making decisions, daring, expressing yourself, making your voice heard, to do things. The result of those things is experience.