Because in Doctor Who proper, when Donna saves the world, we all love her for it–in part because over her whole season we’ve been coming to love Donna–and then we’re all pretty traumatized when Donna has to forget.
While in SJA, when Chrissy saves the universe, we still cheer, but we’re also more content to have her forget everything–she’s Chrissy, after all, and unlike Donna she didn’t grow on us over the past season and we never really came to like her. And then, at the very end, we learn Chrissy’s remembered after all. She may even get to take something away from having done so, and have a chance to be better for it.
And only when she reveals she remembers do we (well, I, anyway) begin to respect her a little after all.
Still sad to see Maria leave. I love how this show has been, essentially, an adventure series centered around a multi-generational friendship between women.
I hope Maria finds some aliens to fight in America. You’d think that in Washington, DC of all places at least a few would have slipped through in spite of the treaty, wouldn’t you?