Osake to Ocha
Sagara Sanosuke had a preference for sake. His brash nature wouldn't have it any other way. And while he wasn't especially above average in the art of enjoying a good evening of intoxication and buffoonery, he did consider drinking to be among his favorite hobbies; aside from fighting and finding cute women to flirt with.
Himura Kenshin, (in spite of his upbringing by the founder of all alchoholic kenjutsu masters), found himself preferring green tea. In stark contrast to sake, which returned to him the sense of desired forgetfulness, and memories of the taste of blood in his cup, he enjoyed the civility of tea. It was a quiet, mild and unassuming drink, all qualities which he desired to posess. Although he got a hard time for passing up other options, he always found his center over a steaming cup.
They had to compromise, occasionally, more often to Sano's favor than not, seeing as it was easier for Kenshin to adjust into a setting of rowdiness and idiocy, than it was for his gangster friend to mold himself to the chafingly delicate nature of tea drinking. But when they did have their tea, he was a sport about it, even through various burn injuries resulting from trying to drink too fast.
Kenshin once mused briefly over a lukewarm serving of tea, that his intimacy of relationships could be gauged by how much he could stand inconveniencing the other person, if at all. As he thought this, he glanced at Sano's mildly bored face, and although he knew that the other man wasn't especially fond of being here, the fact that he sat through it anyhow, made the Rurouni immeasurably grateful.
He topped off the two cups dutiously, and briefly glanced at the small stalk that floated in the center of his own. It was only the briefest of impulses, that he handed it over to his tiring friend, a tiny smile playing on his lips, as he sweetly said,
"Omedetou."
What he meant was 'Thank you.'
(Notes)
In Japan, a tea stalk floating in your tea is considered lucky.
"Omedetou" means more or less "Congratulations."