The current positivity movement has taught us many valuable lessons about life and how to make it better. Yes, I have argued before that many of these lessons require better explanations than what they are afforded on social media and the short snippets of text embedded in the stampede of "memes" that present them to us.
That we should learn from our failures, for example, is excellent advice; such a concept is fundamentally useful to our performance in any endeavour and our personal development. It is essential for our self-growth. The recommendation often takes different forms: one iteration is that we should not fear failure, something that on its own may do more harm than good, because it can imply that failing is a viable option with minimal effort.
It should be said that we need not fear failure if we have done our best - if the maximum possible effort has been put forth.
Nevertheless, the value of the notion stands, we should indeed learn from our failures and mistakes - they can show us parts of a process upon which we need to improve. Our mistakes, if we pay close attention to them, can makes us better people. Furthermore, accepting accountability for our behaviour and its consequences will point us towards better practices and reduce the likelihood of revisiting our shortcomings.
Accepting the burden of responsibility for what you have done wrong is difficult yet psychologically freeing in the end. The point of this exercise in liability is to move onto states of good conscience for yourself. Conditions in which you can forgive, accept, and love yourself and others properly.
Similarly to the guidance to learn from your mistakes, this caveat requires a little more explanation. Do not dwell in the past for too long when analysing your mistakes - see them, find the lesson, and move forward to rectify them if necessary. I strongly recommend speaking about your failures openly with someone whose judgement you trust to be objective; someone with whom you have an unemotional relationship or someone who is not afraid to "hurt your feelings". Frame the conversation with your search for feedback and honest attempt to procure self-improvement knowledge.
I can tell you from personal experience that this can be extremely difficult depending on the perceived severity of your mistake; however, it will eventually be one of the most liberating steps you take towards positive change.