Read this a while ago - a few things I think now that I attribute to the book:

systems work most of the time, and it's because people generally can figure out how to do the right thing
sometimes systems fail, because people did not figure out how to do the right thing
* when a tense situation is unfolding, the people involved are making choices that make sense to them in that context. If the choice turns out to be wrong, that is regrettable, but also, "it was the right idea at the time."