"Great! Do a little miracle, wiggle your fingers about, Nina falls for Maggie, problem solved." "Miracles don't work like that."
I have always wondered about this exchange. Why is Aziraphale the only one who knows that miracles don't work like that? Because Crowley doesn't know or he wouldn't have suggested it, and the archangels obviously don't know either or it wouldn't have even gotten to the point of them sending someone to verify the miracle.
I don't know, it just seems odd and I can't think of an explanation that makes sense.
Doylist explanation: author doesn't like love spells and would not want Aziraphale mucking around with them, either for "ew consent issues" reasons or for "boring plot device" reasons.
Watsonian explanation: Aziraphale knows that miracles are about choices and that love works the same way as other feelings: you can inspire but you can't force. Crowley doesn't know this because Crowley hasn't stopped to consider love as a feeling. To him it's something you do, not something you feel.
I've always had a thought that there is a difference between what sort of "miracles" are available to angels vs demons. The only evidence I have for this is the 1941 church scene where Crowley says, about the bombs, "It would take a last minute demonic intervention to throw them off course" and then "it would take a REAL miracle for my friend and I to survive it."
So perhaps Crowley doesn't know that you can't miracle people to fall in love because, as a demon, he doesn't have the ability to do "real" miracles and therefore doesn't know what sort are available to angels.
I get this, and that dialogue has always been faintly off to me too (including grammatically, argh), at least as delivered. But Crowley's had to do angelic miracles for The Arrangement, surely?