There is a strong counter-meme, mostly pushed by the 37 Signals crew, that failure is overrated. You can learn more from success than failure. You can dissect success to determine exactly what actions were the cause of the success. You can see the forest for the trees and eliminate the actions that actually did not contribute to success. You can figure out how to repeat the successful actions.
Fred Brooks begs to differ:
You can learn more from failure than success. In failure you’re forced to find out what part did not work. But in success you can believe everything you did was great, when in fact some parts may not have worked at all failure forces you to face reality.
So which is better, learning from success or failure? The real answer is that you should always be learning. When you fail, look for the primary reasons for that failure. When you succeed, don’t let confirmation bias cloud your judgement as to why you succeeded. There is no controversy.
The most important relationship you need to have with failure is well summarized by J.D. Roth:
One of the reasons I used to talk so much without acting is that I was afraid of failure. I’m not sure where I learned to be afraid of defeat, but that’s the way I was. And when I did try something but failed, I’d give up. This is no way to get stuff done. Talkers let fear of failure keep them on the sideline; Doers overcome fear and move on, and when they fail, they simply try again.
Most all who have succeeded have also failed. Learning from these failures is important. The much more salient factor is to continue doing.