How did WWI shape the culture and society of Europe?

• After WWI, new ideas about society formed that appeared significantly different from former Enlightenment schools of thought. Rather than worshipping progress, most people during the "Age of Anxiety" renounced this Enlightenment ideal.
• Each one of these people signified the departure from the old idea of "progress" that was celebrated during the Enlightenment. European culture adopted an undertone of pessimism in the form of modernism after WWI.
• Freud was a pessimist, arguing that man is bound to suffer neuroses whether it comes from giving in to man's irrational nature or by depriving man's irrational nature through society. In Civilization and its Discontents, Freud highlights the ways in which society frustrates the "id," or the instinctual side of man. He argues that people use arts, religion, and literature as distractions from their neuroses. This shift from Enlightenment to modernism, which was marked with pessimistic views on humanity, was common in post WWI Europe. This Freud is known for being the first person to practice psychoanalysis and he dedicated most of his life's work to studying the mind.

• Like Freud, Nietzsche also renounced the Enlightenment ideals. He proclaimed that "God is dead" and was a critic of traditional European morality and religion. In many of his works, he discusses the problems of believing in anything and is very existential. He questions facts and instead calls them interpretations. No longer believing in the Enlightenment ideal of pursuing the truth, Nietzsche felt that truth is not a real thing. 
• Picasso was an artist who expressed his pessimistic and modernist ideas about society through his paintings. Most notable was Guernica, which depicted the suffering of the people of Guernica as a result of war. This painting became associated with the anti-war movement. It uses the technique of cubism.

Guernica

• Duchamp was an artist who rejected many of his contemporary artists for only creating "retinal" art that was pleasing to the eye. Instead, Duchamp focused on art that served the mind. His work is closely associated to Dadaism, a movement that emphasized the illogical and absurd side of man. Dadaism also rejected traditional forms of art and culture and Duchamp created several mockery pieces of art.