What do you think about that really 'not like Aziraphael' smile of Aziraphael's at the very end of the credits?
Honestly, I have half a dozen competing theories about it in my head.
My favorite theory comes from a sentence from one of the fanfics I shoved into the back room a couple years ago (aka I never finished/published it). The sentence goes something like this:
Whenever a fresh wave of paranoia came over him, he would force a smile back onto his face, and think of the greater good. At one point, he had a seatmate. Somewhere between the fourth errant smile and tenth, Aziraphale had looked up to discover that his seatmate had unceremoniously abandoned him.
Like -- you know how they say doing a power pose will literally make you feel more powerful, or forcing a smile or a laugh will literally release happy chemicals? That's what I feel like he's doing at the end, and it looks just as deranged as I imagined it would when I wrote that sentence (hence scaring off the poor seatmate).
He honestly looks a bit off his rocker, and I think he kind of is. He went from an emotional high of landing this massive opportunity (so he sees it), to having his balloon popped in one fell swoop by Crowley. He almost didn't go, but then decided to anyway. He must be so amped up on every emotion in that moment. There's tremendous pressure, both from the Metatron/Heaven and his own determination that he is NOT going to be proven wrong about this.
There's moments in his expression -- those little micro flinches Michael Sheen is so well-loved for, where you can see the facade beginning to crumble. You can see, like beams of light filtering their way through cracks in the clouds, where the gravity of it all starts to pull at him again. He then quickly repairs those cracks, perhaps by reminding himself of all the wonderful and beautiful things he thinks Heaven should be, all the things he wants to do.
Another smile. He's not an idiot. He'll show Crowley. He'll show them all. He CANNOT break. It's too late, he's already gone. He's in it now, and especially now that he knows what's at stake (the second coming), he has to do this, in his mind. And he will. He's going to. He stopped the apocalypse! He's honest and a leader! So Michael and Uriel still hate him -- he has the Voice of God at his back! They won't ever do to another angel what they did to him.
The final smile, covering up the biggest doubts. He's going to do this. He HAS to do this. It's time to stop thinking about what just happened. He's about to step into a hive of bees, and he had better hope the colony doesn't reject him as their new leader.
And they won't, he's assuring himself. That bigger smile, the one that somehow crinkles his eyes -- because he knows that's what smiles are supposed to do -- but never reaches them all the same. I think he's wearing that smile the way Crowley wears his glasses, with his real feelings buried deep inside, where no one can find them -- not even himself. Because he can't let that happen. Because he has to succeed.
here’s the cut opening scene from daleks in manhattan if anyone cares/has not seen it idk. anyways my favourite part is the eleven seconds of pure silence + tardis rattling