At the beginning of World War I, Great Britain had a small, professional military. It had an army built to police the British Empire, protecting his majesty’s possessions against insurgencies, such as those in South Africa and Afghanistan. The Royal Navy, the greatest in the world, protected the island nation from any assaults on its territorial integrity.
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.