Mistakes are the best experience and learnings you could take.It is really just there are people who cant really just accept their errors or mistakes and tend to stop completely rather than on making learnings from it
some mistakes are better avoided than learning from them because of the weight it may carries, that's why some prefer learning from others mistakes than theirs, while as for those that dont keep to learning or being corrected, it will surely cost them than it will benefit them.
we also can not only depend on the theory that is taught when we are in the learning stage, be it at school or college, because still theory will not work properly if it is not accompanied by good application and of course experience too. take effect.
you're right, that's why many go with the word that says experience is the perfect teacher, and is one of the easiest ways to knowledge acquisition, no matter how rich and educated a child is, he can never have the live experience of a grown up adult.