Sigmund Freud's exploration of the human psyche was motivated by his quest to understand unconscious processes and their impact on behavior. His early work in neurology and later studies with patients led him to develop theories about repression and psychsexual development. Freud sought to unearth the hidden influences of past experiences on present behaviors, which led to the creation of psychoanalysis. His groundbreaking work aimed to alleviate psychological suffering, revealing deep insights into human emotions, desires, and conflicts, shaping the landscape of modern psychology.