Harry's never let anything get to him. He's always been really strong emotionally, not letting the worst hurt him. The Dursley's always told him he'd never get anything he wanted; love and friendship. He's always been repressed and has never known anything else. Draco has always had his life chosen for him. Be a death eater, kill Dumbledore, never stray from the path. Draco has never known anything but order. Draco and Harry decide it's time for a change when they go to Hogwarts for another year.