"THE GREATEST TEACHER, FAILURE IS" said by one and only, The great master Yoda. This has got to be one of the best dialogue i have ever heard and there is so much you can take from such a simple line.
What i have seen is that people usually end up being demoralized by the failures in their lives and quit believing in them selves. In my opinions failures are to remind us that we are humans, that we are not perfect, that we can make mistakes, but what we take from this is completely up to us, whether we want to use them positively or negatively, whether we want to sit back and cry over the mistakes or whether we get up and fight back.
Failure and success is all part of this life and we should appreciate both as they teach you a lesson in one way or another and that is what experience and wisdom is.
ALL HAIL THE GREAT MASTER YODA AND MAY THE FORCE BE WITH YOU.
(Picture copied from google)