E.E. Cummings' life experiences, particularly his time in World War I and his exposure to avant-garde movements, significantly influenced his poetry. His rebellion against conventional grammar and structure reflected his desire for artistic freedom and individuality. Cummings' fascination with relationships and nature also emerged from personal encounters, allowing him to convey deep emotions through unique syntax and imagery. His experiences with love, loss, and the challenges of societal norms allowed him to craft a voice that celebrated humanity in all its complexities.