How did things change during modernism?

The way things changed during modernism is that before people thought that the wold was getting better. Then after the war people started saying that the world isn't getting better.Some people believed that art was suppose to be beautiful, then some started to say that art is ugly, and everything is ugly. When the war was barely starting some people started to say that war was like a game.Some of the soldiers hat came back had a lot of flashbacks. Some of the flashbacks were so violent and so terrible that some of the soldiers were put on suicidal watch. Most soldiers couldn't stand a whole day working because of the flash backs.