Why don't leaders learn from success? The first reason cited is the 'fundamental attribution error' -- "When we succeed, we’re likely to conclude that our talents and our current model or strategy are the reasons. We also give short shrift to the part that environmental factors and random events may have played."
Humility is a good thing. http://hbr.org/2011/04/why-leaders-dont-learn-from-success/ar/1
Why Leaders Don't Learn from Success - Harvard Business Review
A common joke makes the same point from the other direction:
“Good judgment comes from experience.We’re much more likely to look hard at what we’ve done or not done when it isn’t working well, or when others have questioned it.
Experience comes from bad judgment.”
We could learn a lot more from our successes but usually only “learn” that we’re too smart to need to learn anything more.
Postscript: in today's Chicago Tribune provides this illustration: "'Hitting, we don't even talk about too much because if it's going well you want to leave it as it is,' [Carlos] Quentin said after going 3-for-4 with a double and home run."