The Konoha jounin and ANBU always say that, no matter how far up the ranks you crawl, you are still an Academy student until you gain your first scar and see your first death. They say that the mark of a true ninja is what sacrifices he makes. Sasuke would like to think that, in the curving, climbing, deathward chase after his brother, he has made that sacrifice.
He has made many sacrifices over the years, each feeling as forceful as a punch in the gut but with a long, lasting ache instead of a mere sting. But the sacrifices of his childhood, his pride, his honor, and his home all blended together in his mind until he could not distinguish between them. There was, truly, only one sacrifice that stood out in his mind.
As much as Sasuke would like to believe he resents sacrificing himself, the burning truth he could not ignore was that the only sacrifice he regretted was that of his genin team.