I guess I'm in philosophy mode this morning. Your comment about "one small part" reminded me of this little ditty.

For want of a nail a shoe was lost. For want of a shoe a horse was lost. For want of a horse a rider was lost. For want of a rider a battle was lost. For want of a battle a war was lost. For want of a war a kingdom was lost. And all for the want of a horseshoe nail.