They aren't necessarily the best scenes I've watched in anime. I mean, I do think both of the scenes I'm going to talk about really are great (though one also has its problems), and that's no doubt part of why I react so well to them, but that's not really the point.
They're both intense and dramatic expressions of terrifying, destructive love from one female character to another.
The older one, not that anyone is surprised to hear it from me, is from Mai-HiME, which is in a lot of ways a pretty stupid show that's willing to do anything for fanservice in the side materials and parts of the anime itself. But sometimes, sometimes it pulls through.
Over the course of episodes 22 and 23, Haruka and Yukino confront Shizuru where she's sheltering Natsuki and catch her briefly kissing Natsuki while she sleeps. Haruka tries and fails to get Shizuru to come back to her duties as school president--all she cares about now that she's emerged from the shadows as a HiME is protecting Natsuki. She's throwing everything else away. Yukino, seeing Haruka's distress at being so utterly unacknowledged by her long-time rival, defends her--and threatens to expose what Shizuru's done here with Natsuki. Of course, Natsuki has woken up and is listening, and she puts Yukino's words together with her own confused, muddled fever-dream fantasies about Shizuru and (so cold and out of touch with her own emotions and desires is she, she can more easily imagine they were something done to her than something her own subconscious mind dreamed up) assumes she was sexually assaulted in her sleep far beyond a mere quick kiss, and by someone she trusted and relied upon too. She runs to confront Shizuru as well and reacts with revulsion when touched. And Shizuru is so mired in her own desperate repression and inability to accept her forbidden love that she assumes that of course Natsuki is reacting so badly simply to finding out that Shizuru loves her that way.
[A note on the feminist anger over this scene in yuri fandom.](It's complicated. The show has a terrific thing going here but really, really doesn't do a very good job of explaining it or clarifying the very loaded subjects it brings up. Some people seem to have grasped right away that the show was trying to convey Natsuki misunderstanding her own incoherent dreams, but a lot of people didn't--it took me a while to pin it down fully myself. The show didn't do much else to explain later, because goddammit, Sunrise. A lot of understandably bitter viewers ended up coming away with the impression that Shizuru raped Natsuki. Anyway, this is a vile fanservice-filled seinen anime with a lot of definitely problematic things in it, so it can't possibly also have any nuanced examinations of young women dealing with their complicated and troubled romantic feelings for each other, so of course that's how it happened. People often hold up the popularity of Shizuru/Natsuki as a prime example of how disgusting and deluded yuri fans are. I know where they're coming from, but it's frustrating, and I'm kind of on edge whenever I bring it up now because of that history, hence this digression.)
And so, with all the walls around her unspeakable unacceptable feelings being torn down around her, with the fragile foundations Shizuru had rested everything in her life on falling to pieces and leaving her with nothing at all to hold onto but her desperate and terrible love for Natsuki, she gives up trying to hold it in anymore, and she destroys Yukino's summoned Child and so erases Haruka (as Yukino's most important person) from existence, and she leaves in order to destroy all of Natsuki's enemies and everyone who might threaten her with no more heed at all for consequence...
But my favorite moment is actually the one at the end of episode 22 and the very beginning of episode 23, before Natsuki has revealed that she was watching, but after Yukino has made it clear that she won't let Shizuru get away with ignoring Haruka, running off to be with her girlfriend, and leaving her duties as school president in the dust--she'll expose (what they assume is) her relationship with Natsuki if she must. And Shizuru, who knows that Yukino is also a HiME even if Yukino is not aware of the same about Shizuru, says something to Yukino. How it's translated differs in a small but significant way between the two versions I've seen--[SS] fansubs and the official one. Normally I'd give the official translation more credit until hearing a more detailed explanation from someone who knows Japanese, but Mai-HiME's official translation has a tendency I have previously noted (in discussing the final battle between Mai and Mikoto) to confuse and minimize important relationships (both platonic and romantic) between the female characters. In the case of Shizuru/Natsuki, this seems to manifest as them playing up the awful and unrequited nature of Shizuru's feelings while downplaying the possible of Natsuki reciprocating. I'll give both translations. You decide.
In the fansub I have, Shizuru addresses Yukino with, "If it's for my dearest one, I will do anything. Do you think like that?" And then she summons her Element, her magical HiME weapon, to challenge Yukino and her offensively useless espionage-oriented Child to a fight that will cost Haruka's life if Yukino loses. In the official subtitles, she asks, "Do you also believe that you can get away with anything, if it's for the sake of the one you love?"
There's just something about her broken expression there, as she realizes how far she's gone and how far she's going to continue going, and the terrible flat calm of her voice (I love Naomi Shindou's performance here so much). It gets me on a level deeper than any sophisticated critical reasoning every time.
That part of the scene is up here on Youtube for now.
The tenth episode of Madoka Magica is pretty different. I don't have as much to say about it, because I'm still processing the whole thing. It's new to me in a way Mai-HiME isn't. Even apart from my personal feelings, this episode is one of the best I've seen in anime, and this scene is amazing.
It's the end of the third timeline. Homura has gone back in time twice now in a desperate attempt to save Madoka from death or an even worse fate. Now, after the utter turmoil of the revelation about how witches are born from despairing or exhausted magical girls, Mami's reaction, and Homura and Madoka's last bid to defeat Walpurgis Night, the two of them are lying in despair in the aftermath of the final witch's destruction. They won, but they used up their power and are about to transform. Madoka says she has no more Grief Seeds left with which to purify their Soul Gems and save them.
Lying there next to Madoka, Homura says quietly, "Hey...if we were to stay like this, and become monsters together...would you like to make a mess of anything and everything in this world? All of the unpleasant things and all of the sad things...until they're all wiped from existence, we'll destroy, destroy, and destroy more. If we did that, don't you think it'd be nice?"
And then Madoka takes out the last Grief Seed that she lied about not having (which would incidentally appear to be Oktavia's) and uses it to purify Homura's Soul Gem. Homura is horrified. But Madoka tells her that she has to survive and return through time again, because she's the only one who can. She's the only one who can save Madoka, by stopping her from making the contract to become a magical girl in the first place. She begs Homura, in so many words, to save her. And that's the final push Homura needs, this time when she turns back the clock, to take up the mantle of protector completely, erase her vulnerability, and start the fight to save Madoka in earnest.
But really, though, it's her speech about becoming a witch together with Madoka that gets me. That willingness to throw away the world for the sake of a desperate love. I'm sure I've seen it elsewhere in heterosexual romances, but I guess somehow it gets through to me more when it's between two women or girls.
I don't know what to make of it. Probably I shouldn't take any of this too seriously, and neither should you.