In 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[The cause of inaction in war] ... is the imperfection of human perception and judgment which is more pronounced in war than anywhere else. We hardly know accurately our own situation at any particular moment while the enemy's, which is concealed from us, must be deduced from very little evidence.
Carl von Clausewitz