The men and women who fought in World War II faced a combat situation unlike any other in history. Larger, more powerful weapons, difficult combat conditions, and a heavily armed, extremely tenacious enemy plunged soldiers into the horrific situation of kill or be killed. While most commanders were battle-hardened veterans who had honed their skills in World War I, the overwhelming majority of grunt soldiers were inexperienced young men. Most managed to cope fairly well under these difficult conditions, but some did not. Combat fatigue was a common problem — particularly among those who were involved in long campaigns in which heavy fighting was a daily occurrence.