The word "failure" needs to be better defined. It has a dark cloud hanging over it and it really shouldn't. We learn from trying, failing, and trying again. It is a natural part of the process of life. As a young "executive" in retail I was taught that there are two kinds of people who never fail. The first is someone who never does anything and the second is dead people.
I've noticed there are students who do not handle any kind of failure very well at all. If they make any mistake in learning a new piece, or if they have difficulty learning a new technique they are just devastated. I've seen complete meltdowns over a simple, and very common difficulty. When I try to reassure them they act as if I'm just saying nice words to stroke them along. I'm reminded of the difference between a student and a teacher...... "a teacher has failed more times than the student has tried."
I'm gratified that many other students handle failure with grace and humor. "That sounds awful", they laugh. Then they will play it wrong again on purpose just to have an excuse to laugh some more. A moment later they will play that passage again, slowly, correctly and repeatedly until they can play it right.
All of my students are taught my four word definition of the word "practice". "Practice is problem solving". It pre-supposes that mistakes will be made and early attempts will fail. Some students can recite the words and not understand the meaning or its ramifications. And this is not related to age or maturity. I can get positive or negative reactions from young and old.
With students who are interested in composing or arranging I advise them to listen closely to their mistakes because that's where the new stuff is hiding. I've written new music or enhanced arrangements of songs using the results of doing something wrong in another song. Just because the note you played is incorrect doesn't mean it's wrong.
In a military mission and certain other endeavors the phrase "failure is not an option" is often used. But in matters of education and creativity failure IS an option and a valuable tool. We use failure as a way to advance our purpose. I suppose these two activities can give us either functional or dysfunctional failure. When learning becomes a mission the lines between these two distinctions can become blurred.
So I guess the slogan of the day is: "If you don't learn to fail then you will surely fail to learn."