Disclaimer: I don't own Harry Potter or related subject matter. I barely own the plot.
Warnings: This is slash. It will only get slash-ier.
Severus Snape had kept many lists in his long, jaded life. While some were of the traditional sort, those being comprised of parchment and ink, most of his lists were kept in his incredibly well organized mind. Lists of his classes, his students, his books, his potions ingredients, his things-to-do, and his survival guidlines. Some of his lists were very long, such as his list of enemies. Some were very short, like his list of friends (though he wasn't sure if a list with one, deceased wizard on it could be a real list). Some of his lists were mundane, like his list of chores. Others were very personal, though. The most personal list (and the longest, too) was a list of the things that he would miss as he got older...
Harry Potter, hero and formerly ex-aurorer, stood in front of the counter at the smallest shoppe in the darkest corner of Diagon Alley. The sign hanging above the door read Potente Philters and Effective Elixirs, and an unassuming plaque in the front window stated: Proprietor: Severus T. Snape.
Item 1: Balance.
Potter was back. Bloody Harold James, Boy-Who-Lived, Man-Who-Saved-All Potter was standing in front of him. The menace had been gone from his sight and thoughts for exactly six years, two months, eleven days, and two minutes, and now he was back. Why? What could the cretin possibly want with him? Snape had already been tried and exonerated, and only because of the aforementioned brat's testimony. The retired auror could hardly arrest him, at any rate. The potions master rolled his wand in his hand under the top of the counter, a fierce scowl snapping into place. Fire blazed in his deep, black eyes and his spine was ram-rod straight.
That this Potter was different was quickly apparent, and it made him anxious. Well, even more anxious than he would usually be while dealing with Gryffindors and/or aurorers, that is. Snape was nervous by nature, and heroic Gryffindor idiots brought out the worst in him. And while this Potter was distinctly of the Harold James variety, he had changed. He was older, for starters, but why would that surprise him? It shouldn't, he supposed, because people did change, even as Snape did not. Which is exactly why Snape barked, in exactly the same Snape-ish manner he would have used while teaching the boy at Hogwarts, "POTTER? WHAT THE HELL DO YOU WANT?!"
The reaction he recieved was not at all anticipated. The damn brat had the audacity to SMILE! So, Potter thought he could just waltz into Snape's shoppe and MOCK him after YEARS of blessed ABSENCE?! No. "Get. Out," Severus hissed through crooked and clenched teeth. The Potter brat's insufferable smile did not waver. If anything, it grew and his eyes crinkled at the edges, and this made the older man's stomache clench apprehensively.
"I rather think, sir," he replied, sounding nearly sincere (the bastard), "that that would defeat the purpose of my coming here."
"And I rather think that I don't CARE why you're here, so long as you leave IMMEDIATLY!" was the eternally vexed interjection.
"I can't leave. I mean, I really can't, even if I wanted to. I'll explain it to you in a few minutes, but first, why don't you close down the store so we can talk at your place? Upstairs, right?"
Snape just sputtered, rather red faced, while the thrice damned brat had the nerve to lock the front door and reverse the magical lettering on the door from 'Open' to 'Closed.' Before the perplexed ex-proffessor could even utter a properly scathing admonition, though, Potter spoke again in a more serious tone.
"This is official Ministry buisiness, proffessor. Let's talk upstairs." Of course it was. Severus sighed to himself and his stomache sank. He had no choice but to lead the way into his private home, where he just knew things would end badly.