In the summer of 216 BC, during the Second Punic War, the Carthaginian military leader Hannibal, after his epic crossing of the Alps, led his numerically inferior army into a battle that would end with 50,000 Roman infantry killed. The Battle of Cannae effectively destroyed the Roman army as a fighting force. One of the major problems with the Roman army during the battle was the lack of a unified military command. When two consular armies joined forces, as was the case at Cannae, and fought as one unit, the consuls would exercise command on alternate days. This resulted in confusion about who was ultimately in command of the army.
Benjamin Franklin nailed it when he said, "Fatigue is the best pillow." True story, Benny. There's nothing like pushing your body so far past exhaustion that you'd willingly, even longingly, take a nap on a concrete slab.