Harry saw young Snape listening to his parents fighting, Snape cursing flies, and Snape's disastrous flying lesson. ... He say his mom and Snape being childhood friends. Then he saw Snape being abused by his father. Finally, he say Lily die at the hand of Voldemort. When they returned to the castle, Harry secretly proceeded to Dumbledore's office, where he watched Snape's memories. He saw the child Snape meeting Lily and Petunia Evans, and telling Lily that she was a witch, and how Dementors guarded the wizard prison Azkaban. Ok
