The reason why the protagonist of Cervantes's novel Don Quijote was "crazy" was that he suffered from the pressure and constraints of the aristocratic society, which led to his mental breakdown and the symptoms of "madness". In the novel, Don Quijote was portrayed as a knight full of imagination and idealism. He tried to resist the oppression of the aristocratic society but found himself trapped in an unrealistic fantasy. Don Quijote's "madness" reflected the reality of Spanish society at that time and the exploitation and oppression of the lower class by the aristocrats. At the same time, this also highlighted Cervantes 'deep insight and criticism of the society at that time. He deeply revealed the dark side of the society through his novels.