The difficulty of accurate recognition constitutes one of the most serious sources of friction in war, by making things appear entirely different from what one had expected.
Carl von ClausewitzKnowing is different from doing and therefore theory must never be used as norms for a standard, but merely as aids to judgment.
Carl von ClausewitzIn War, the young soldier is very apt to regard unusual fatigues as the consquence of faults, mistakes, and embarrassment in the conduct of the whole, and to become distressed and depondent as a consequence. This would not happen if he had been prepared for this beforehand by exercises in peace.
Carl von Clausewitz