Most real lasting lessons learned are not learned in safe vacuums void of pain and conflict. Deep teaching and learning frequently happens when difficulty and sacrifice are present. Typically those who occupy the highly successful occupations have endured lengths of time, usually spent in difficult activities and delayed gratifications.
It is important to understand that failure is and it can get complicated when trying to understand what level of failure needs to occur for teaching to be present. From the basics of memorizing spelling words to honing skills of welding. From memorizing decision trees of medical diagnosis to using robotics to assist in brain surgery. From following a recipe to bake box brownies to making a multiple course dinner at a 5 star resturant. There are many levels of practice, failure, and success.
Failure happens in life at many levels. It is not important how much failure one goes through or how much failure needs to happen to find success. It is important to respond appropriately and directly to failure. A passive response to failure will not lead to success compared to active response. Difficulties and failures hone skills, mentalities, and develop the maturity level of the individual. Failure is complicated and hard to understand which is outside the scope of this writing. What is important is not the failure specifically but the focus on the development and learning that can take place through failure. Failure is not the end but the beginning of something. It is important to look at the failure, experience it, rest for some time and then learn from the experience. Teaching can happen in many ways, the most significant ones can happen through and after a failure.