Disaster is in the Details
Little details matter because they prevent big disasters. This might seem counter-intuative at first; logically it seems like big disasters should have big causes. In reality, they have a series of little causes that add up into a big problem:
Disasters Don’t “Just Happen”
One of the first things I learned in flying was that airplanes don’t just fall out of the sky. (This, by the way, comes as welcome news to the student pilot.) Airplane accidents can almost always be traced back to a series of mistakes and events: The night was dark AND visibility was limited by fog AND the area being flown over was water, lacking in reference lights, AND John Kennedy, Jr. had only a few scant hours training in instrument flying AND he was flying illegally based on his visual flight rules license, perhaps causing him to hesitate before asking for help AND….
The investigation of the near-meltdown at Pennsylvania’s Three Mile Island nuclear power plant in March, 1979, listed a remarkable series of seemingly disconnected events that converged to almost cause a major disaster. Along with other causes were such human factors as lack of operator training and a confusing and misleading control layout. As with many disasters, the series of events that arose from a single trigger could have been short-circuited at any point, had anything gone right.
This is why good design is especially valuable. In isolation, fixing a small detail only seems to have a small benefit. But if that one small fix breaks one small link in a chain of events that would lead to a disaster, then there is enormous benefit.