Things I'm noticing on rewatch
Aziraphale knows how reproduction works (and realizes you need a pair) because (unlike Crowley, rip unicorns) he saw the human design plans, if maybe didn't directly work on them. Presumably there are other angels who know, it's a good thing that none of them were tagging along for the whole Job bit. Or maybe they just didn't want to contradict Gabriel.
The "this way up" sign on the box is so cheeky. Aziraphale and Crowley could've solved the whole mystery if they'd just ignored the rules and upended the system box, but there's still part of them (esp. Aziraphale) still instinctively following the rules.
Literally the first thing they say to each other in the present sets up their entire season conflict of not communicating properly, while being hidden in a joke. *groans loudly*
okay wait did we figure out what the deal was with this getting so specifically highlighted?? I've tried looking up the passage and I am.. still pretty baffled. Other than the obvious connection to Crowley being about to explode in a few minutes.
Edit: There's a theory I like quite a lot here, though still open to other interpretations if you've got em!
Crowley opening the door for Aziraphale and Nina staring in fascination is SO funny. She's just dying to know what tf is going on there.
Originally overlooked this bc it's not his usual coy heart eyes, but this is an Ask from Aziraphale. Aziraphale glances to Jim and back like, Well I'm not doing that.... and Crowley gets the message that this is (at least partially) why he's here, to be the demon and not the nice one.
Really can't get over the walls matching Crowley's eyes. You can't leave this bookshop indeed.
Despite the fact that Crowley is storming out of here so angry that he will literally explode in about 60 seconds, he does not slam the door. It's not the bookshop's fault / he really is trying to control his temper / he doesn't want to leave things on that final of a note / choose your interpretation.