I once worked with a General Manager who came from The Bronx, NY, USA. It was a tough neighborhood where he grew up. He said many of his childhood friends were either dead or doing time in US gaols (jails).
He had a long list of experiences setting up factories in China and Taiwan. He could tell the thickness of a piece of paper down to a decimal of an inch just by looking at it. He married a Taiwan lady and eventually settled in Singapore. He was in his late 40s.
We were discussing an additional production line we had just set up and was ready for production. Going through all the equipments wasn't enough for him. He wanted to check the material inventory as well. He was right of course. We couldn't just take things for granted that they'll all be there like clockwork. Someone has to wind up the clock too.
We found that the screws were not in. Those were special screws. Stainless steel. They had to be flown in from the US.
And here's the story he told me that day.
A great general was about to go into a crucial battle. It was one that would decide whether they won or lost the war. He told his men to get ready. They checked all their weapons, supplies, food, equipment and transport. All seemed perfectly organised. All, except one little detail that their stable hand did not mention. A nail was missing from one horse-shoe on the general's horse. He thought little of it. Only one little horse-shoe nail. Beside's the general had several horses he could choose from. But that happened to be the general's best horse.
For crucial battles one always choose the best. It was to involve a lot of hard riding, covering many miles over rough terrain and difficult maneuvers.
In the thick of the battle the general noticed his horse limping. But it was too late. The horse went down taking the general with him.
They lost the battle and they lost the war.