It is usually the smallest of things where difficulties happen. The things one would never think of or even notice. The simple things that get done unconsciously and without our being aware that they even exist. The things we take for granted.
In my decades of working with leaders at the global level, the difficulties were always in this area, the 10% arena. These small, undetectable differences almost always caused the most problems.
Most of us are unaware of these tiny subtleties and would never imagine that understanding them could have such a huge impact on the outcome of things.