Learn to see in another’s calamity the ills which you should avoid.

When something goes badly wrong for somebody else, the usual response is either pity or a quiet sense that it could not happen to you. Both responses skip the useful part, which is the sequence of ordinary choices that led there. Very few disasters are caused by one dramatic error, and most are built out of small tolerated things that anyone might tolerate.

Take a situation you watched go wrong and trace it backwards to the first point where it could have turned. Ask honestly whether you would have recognised that point. If not, that is the thing to learn, and it costs you nothing to learn it this way.