Surrealism and Un Chien Blogdalou

As Buñuel himself stated of his film Un Chien Andalou (1929), "Our only rule was very simple: No idea or image that might lend itself to a rational explanation of any kind would be accepted. We had to open all doors to the irrational and keep only those images that surprised us, without trying to explain why”. I find it fascinating and rather hard to believe that what drove both Buñuel and Dali to produce this film was, as they claim, simply to shock filmgoers, "to disrupt the mental anxiety of the spectator”. This leads me to the question: why did Buñuel and Dali feel the need to pioneer a movement that sought to shock, even offend the viewer? In response, it is my belief that Un Chien Andalou, along with other films of the Surrealist movement, was actually intended to push the idea of film as an artistic medium; Surrealism worked for other artistic disciples, why not film too? This would at least justify the film’s illogical structure and the fact that each frame of the film is nonsensical, with intentions of projecting an emotion, not a narrative. Whilst Un Chien Andalou still makes very little sense to me, perhaps it is filmic Surrealism in its purest form.