That's a bit heavy for a Sunday morning, isn't it? I mean, that seems much more like a Monday morning topic to me, or perhaps a Friday night over drinks topic, because to answer the question one has to first determine what their biggest failure was. Nothing like opening that particular box, eh? I mean, we all have one - that box of failures that we keep shoved back in the dark recesses of the closet of our minds. However, I must say that, for the most part, when you do pull that box out, dust it off and look inside, more often than not what's inside really isn't as big and ugly as you remembered it to be. I know I'm a lot harder on myself than anyone else ever has been. Thinking of a list of failures was harder to do than I thought it would be. Nothing came immediately to mind, really.
So, what did I learn from my failures? Well I suppose what I just said is what I've learned. Unless your biggest failure was to go bungee jumping and forget to attach the cord, chances are that whatever it was - you survived it. Regardless of how bad, you may be able to look back one day and realize that it really wasn't that big of a deal. And maybe even that your "failures" ultimately led you to something good in your life that you would have otherwise missed out on.
So, when something bad happens ask yourself if "in five years, will this matter?" There's a good chance that it won't. Oh, but always wear a bungee cord.