I'm of the opinion that Wisdom can be acquired two ways:
1) learn from your own mistakes as you recommend
2) learn from other peoples mistakes
I prefer option 2, it costs SIGNIFICANTLY less time, money, pain, etc..
So, although I agree that you have to do some things on your own, what I was referring to was; out of the things I learn here, the best nuggets of wisdom come from when the conversation takes a tangental subject, and then returns to the original subject. The tangent almost always has some wonderful little piece of gold in it. That is what I am asking about.