The apple scene between Kyoko and Sayaka feels both like "a proper introduction between enemies who no longer wish to fight" and "a final invitation to connect with someone and pull yourself back from the edge".
Sayaka tossing aside Kyoko's gifted apple feels like her making a conscious choice to fully go crazy and a denial of Kyoko's attempt to reach out to her.
Additionally, Kyoko giving away to Sayaka something that holds significance for her (food, which she considers incredibly precious) without any expectation of something in return aside from "connection" is an interesting moment for a character previously depicted as "selfish" and constantly against Sayaka.
Kyoko sharing her story TO Sayaka is a moment of vulnerability, later matched by her sharing her story WITH Sayaka by sacrificing herself when she likely could've defeated Oktavia without dying in a effort to ensure Sayaka wouldn't be alone anymore.
It's mentioned that in every timeline Sayaka contracts and becomes a magical girl, she becomes Oktavia.
I think this says a lot about Sayaka's mental state. Even if Hitomi doesn't confess to Kyousuke, even if Sayaka and Kyousuke were to date, Sayaka would still become Oktavia.
Maybe it's a case of regretting what she wished for, or falling out of love with Kyousuke, or that her relationship with Kyousuke didn't work out how she had wanted it to. Regardless, something always goes wrong when she makes her wish; and I find that very fascinating.
UPDATE: Sincerely unhappy with how this original post came out (too much focus on Kyousuke which reduces Sayaka's character in a way I don't like); please go to the reblog version.