"Because I hate to share. And if you're with Potter and his friends, you're not with me." And he hated that. He was jealous, envious and he wanted Sirius all to himself. He was petty and very aware of it but he couldn't change it. Reaching out, he stroked his fingers through Sirius' hair and then laughed a little. "How do you stand to be this close to someone as revolting as me? I made myself impossible to get near on purpose and yet, you never flinch when you get close. Why?"