QUOTE : Snape knows Harry saw the scene through his mother’s eyes, feeling empathy for the bullied Snape and then shock at the racial slur. If Snape faces Harry, it is like looking into Lily’s eyes while feeling the full force of his shame and regret—yet not having Lily there to receive his abject apology, only the face of his enemy, James Potter. Shame can be unbearable. Snape did what he could to bear it and teach Harry anyway, and Harry’s intrusion destroyed that protection.