Failure only happens when you give up, otherwise it is just delayed success. To clarify further, quitting and giving up are two separate things in my mind. To quit means that something did not bring you any joy or level of fulfillment and needed to be discarded in favor of freeing up that focus for the things that do bring joy and fulfillment to your life despite your adeptness or lack thereof. To give up means that you were fulfilled in the pursuit of the endeavor but ceased due to hardships encountered during the pursuit. That is when failure happens.
There have been many things in my life which I quit. There are only a few things in life at which I have failed. But was it really a failure? Or was it that something far more important replaced that which I pursued and the greater good won out in the end? I will never know.
These topics are so very subjective that what is failure to one is not to another. The one thing that seemingly runs through both streams is the knowledge gained from the experiences in general, whether that knowledge gets integrated and becomes wisdom or get discarded and becomes disdain.