All those people he had known. All those people whose company he had cherished. Each one he had lost, through his own stupidity. He was alone, and would be from then on, as punishment for his numerous wrongdoings, for his many mistakes.
A/N: Rated for room to work.
Edit: I found that my dividing line was missing, so I'm fixing that now.
1. Lily's friendship
Severus Snape was left staring at the closed portrait-hole. That was it. It was the end. He knew he had been pushing their relationship. She could not understand why he enjoyed the company of some of his friends. He had not known how deep her detest for them was. He had not known that he would ever had pushed their friendship so far. Now, after so many years of friendship, of unrequited love, it was finished. He could feel tears burning the back of his eyes but he fought them back. He would not cry, not shed tears for the world which pushed so hard to get them to fall.
"Lily," he whispered brokenly. She had turned her back on him. Anger welled up, not at her - never at her - but at the rest of the world. It was they who provoked him, who had teased and bullied him. It was they who had embarrassed him. And leading this group, leading the never-ending torment, was Potter. He felt his face twist into a sneer at the thought of the boy.
The arrogant prat was everything he was not. Admired, beloved, and popular, the dark-haired James Potter could have nearly anybody in the school. Almost all the girls would jump at a chance to go out with him. But of all the choices he had, of all the girls he could have fallen for, Potter had to have fallen in love with Lily. His Lily. The Lily he'd known since they were both children. The Lily he'd introduced to magic. The Lily he had loved so dearly, so truly, for as long as he could remember. The Lily who now ignored him, who hated him, for calling her the unspeakable word: Mudblood.
And there he was now, rounding the corner towards the Fat Lady. Severus felt a wave of hatred overcome him. Here was his chance. For the first time in a long while, his enemy was alone. Alone and helpless. Seeing nothing but his approaching target, he drew further into the shadow, out of sight behind a conveniently located pillar, and pulled out his wand.
When Potter was within distance, he leapt out and shouted, "Levicorpus!" In his haste, he missed and the spell shot to James's right. Growling, he shot a Bat-Bogey Hex after it, which also missed. The shouts brought several people just inside the Gryffindor common room out, looking to see what was happening.
By then, James had realized he was under attack and retaliated, whipping out his wand and yelling, "Stupefy!" Snape ducked and felt the jet of air shoot right over his head. His blood boiled as he glared at the person who had caused him so much trouble and heartache. He straightened and sent curse after curse at the other boy. With the nimble skill of a Quidditch player, Potter danced around them and shot more spells back at him, to subdue the fighting. His arrogance at the belief that he could be stopped infuriated Snape. He thought he was perfect, he thought with bitter hatred. Well, he won't be much longer!
Wanting nothing more than to hurt, to kill, he screeched, "Sectumsempra!"
The spell was perfectly aimed and cut deeply into James's leg. He looked at the wound in astonishment as pain flickered across his face. Then he fell. The onlookers screamed and backed away as Snape, breathing hard, looked at them, his black eyes full of malice and suppressed anger.
"STOP!" The scream rang out, the only one among the multitude that he fully heard. Lily stepped forward, her face pale with anger. "What did you do?" she demanded, staring him full in the face.
He turned away, unable to look into those brilliant green eyes, to see the revulsion and horror mixed in the grief-filled gaze. He didn't have to see the glare she threw him as she knelt down at James's side. Even that boy was more important to her now. To her, the friend she had known for so many years was gone, replaced by a stranger whom she disliked as much as her friends disliked him.
Behind him, he could hear her, shouting for someone to get Madame Pomfrey and Professor McGonagall. Her voice dropped as she murmured encouragements to the boy whom she used to loath. His vision blurred and he hurried away, hiding his face from the crowd, letting the tears he'd given up fighting stream down his face. He did not look back.