What has happened to the attitudes of the soldiers by this time in the war

When the war broke out in 1914, the attitude of soldiers towards the war was that it will be a short and fun experience. After grasping the reality of the war, the attitude of soldiers soon began to change. the soldiers began to realize that they are all being sacrificed in a futile attempt. The heavy casulties, the terrible living conditions of the trenches and the war taking.