I don't own Harry Potter. Yadda, yadda, et cetera, whatever.
All dialogue in the following is obviously straight out of Deathly Hallows. Only Lily's thoughts are mine.
'I only came out because Mary told me you were threatening to sleep here'
Mary had actually said that she should leave him there, the creepy little greaser, and let Filch take care of him. But Lily knew that if she didn't take care of this now, she'd lose her nerve later. You're far too softhearted for your own good Evans!
'I never meant to call you Mudblood, it just–!'
'Slipped out?' Of course it just slipped out. She knew him well enough to know that he lost all control of his mouth when he was upset. Still though... 'I've made excuses for you for years. None of my friends can understand why I even talk to you.'
That was an understatement. The other Gryffindor girls couldn't stand him. 'That creepy loser,' they would say.
'I can't pretend anymore.' Well, that was true. It was getting harder to ignore the uncomfortable fact that he fancied her. 'You've chosen your way, I've chosen mine.'
'No – listen, I didn't mean –'
' – to call me Mudblood?' That was not what he meant, and she knew it. He had never been particularly good at expressing himself, even when he was calm. 'You call everyone of my birth Mudblood, Severus. Why should I be any different?'
With one of Petunia's best glares as a parting shot, she turned and went back through the portrait hole, leaving him speechless and floundering, alone out in the cold, dark corridor. She sniffed; it was about time he learned to take care of himself anyway.
James Potter and his friends were sprawled over a few sofas near the main fireplace and she could feel his admiring eyes on her as she stalked across the common room. Her stomach did a happy little somersault, but she was careful not to smile and let him see. Too soon, Lily girl, not yet. Patience. She did smile as she climbed the girls' stairs; safely out of sight.
She couldn't help but feel a little guilty despite herself. Severus looked so lost out there, so pathetic, but it had to be done. The other girls didn't like him, and she couldn't blame them. She didn't like him most of the time anymore either. He was annoying and clingy, always needing reassurance about something or other. Not to mention he was downright embarrassing with his dirty hair and clothes and his blunt Manc tongue. And he fancied her. Eww. He had been an alright friend once, easing her way into this world. She had grown up since then; bettered herself. Not so with him. He was still the same coarse little urchin from down Spinner's End. He was unworthy of her, just as Petunia had always said.