Answer:
The reality of war was in stark contrast to the previous beliefs and attitudes Europeans had.
Step-by-step explanation:
Pre-war Europe included many nations that celebrated their military. To fight was to be honorable and glorious. However, in the Great War, warfare was much more gruesome than previously. The introduction of gas attacks, trench warfare, and other technological/military "improvements" caused lives to be needlessly lost for little to nothing in advancements. During and after the war, people began to realize that it wasn't worth it and the youth suffered terribly.