The story of how Aziraphale and Crowley started the Arrangement. Aziraphale lost his faith after the Crusades, and was about to die from depression, but Crowley saved him and brought him, all the while convincing his superiors he was tempting him.
Castiel and Aziraphale both offering to heal Gabriel. Actually, that whole goddamn scene.
A minor one, but Crowley, despite being a demon, doesn't hold a grudge against Anansi for selling him out to Lucifer.