Success vs. Failure

It is said that we can learn much from our failures, but I'm not entirely convinced of that.  From a practical standpoint, all we can definitively learn from our failures is what NOT to do.  It isn't always as simple as merely doing the opposite of what it was that resulted in the failure, because sometimes there are many different choices as to which path to take, and only one correct path.  I think we learn much more from our successes.