When his mother had sent her reply OWL saying she was extremely disappointed in him he had looked sad for a week. Lily put her hand on his back and smiled at him when she saw his hands shaking. "I can't go back home for Christmas…" he said with a weak voice. Lily hugged him close, "Why is she disappointed, Sev?" He felt his heart race and the urge to envelop her in a hug was overpowered by his own disappointment in himself. He didn't cry, there was no point. There was just personal resentment. "She wanted me to be a Slytherin."
Lily parted from Severus and then looked at him with a cautious expression. "It meant that much to her?" Severus didn't yet feel like expressing the reason he'd become a Gryffindor was a mysterious voice in his head that warned him he might lose her for 2 years. Truthfully he was expecting Hufflepuff, it was considered to be the 'weak' house after all. Wasn't it weak to change your mind over a voice in your head? Or, insane, he scowled at himself.
Severus decided to be at least partially truthful. "I…I was put in Gryffindor because being around those people…I was sure that…that I might become someone you didn't like. Someone who hurt others. I wanted to be able to protect you Lily. What kind of friend would I be to abandon you for people who only care about power and blood purity?" Suddenly Severus felt a little bit…better. Better than he had been for awhile. He was a greasy, poor, barely able wizard who's only talents were things that would ruin him.
But as Lily Evans looked at him with an unbelievably compassionate look in her eyes he realized that this was the first time he'd thought for himself. Thought beyond impressing people with magic. He was sure he'd never get over his love for the dark arts completely…but the look on her face made it worth it to be where he was now. "Severus….you really are my best friend! The hat was right!"
Severus blinked, "Right about what?"
Lily grinned, "You really are brave!"