The unconscious way he rubbed at his arms shed a little bit of light into just what sort of addiction the wizard had. Hermione remembered hearing all the warnings about staying away from drugs from her parents. Because they didn't know how dangerous the world was in which she lived, they lived in fear of teenage pregnancy and recreational drug use being her worst sins. It almost made her laugh to imagine their reactions to learning the truth. Perhaps they would've preferred her to end up dead in a gutter with a needle in her arm than where she was. She'd not become a very good person. They would be ashamed if they knew it all. She got the impression that they already were ashamed and they didn't know the half of it.