Ah! My apologies. Thought I was talking to Villiam. My responses may have made less than perfect sense.

I favor Bismarck on this front. It certainly helps if the mistakes are yours, but they don't have to be.

You can learn from mistakes, but you don't learn what it feels like to make mistakes (which is to say, exactly the same as making the right decision).

I also think it helps to emphasize the possibility of learning sooner rather than later; to abort mistakes as soon as they're noticed, rather than when it's no longer possible to maintain them.

That's where humility is important, and where the experience of having made mistakes helps. Making mistakes doesn't feel any different from not making mistakes. There's a sense that I wouldn't make that mistake, once warned about it - and thinking you won't make a mistake is itself a mistake, quite obviously. Less obviously, thinking you will make mistakes, but that you'll necessarily notice them, is also a mistake.