" Rowling gives us a clue in the chapter title: “Snape’s Worst Memory.” We don’t see the whole memory, but for her to give it that title, we can assume that we have seen most or all of what we need to know. Snape is not the one who labels the memory this way; the chapter title is a message from author to reader. The bullying is bad, but Snape has been through worse: these same people almost killed him. The sexual humiliation is bad, but that’s not it, either, or the scene would not have cut off before the attempt to remove Snape’s pants. Rowling is showing that it was Snape’s own response to Lily that makes this his worst memory. "

― Lorrie Kim , Snape: A Definitive Reading