The entire lunar eclipse ritual in Moonah Ston. Featuring hopping, dancing, howling, and Thomas trying to recite the reading dramatically over the Captain and all the other noise.
Draco in Leather Pants: A very mild example but the audience love Pat and find him completely adorable despite his actor Jim Howick describing him in interviews as "a bit of a prick".
Ensemble Dark Horse: The Captain has become rather popular on Tumblr, moreso than the other characters.
Jerkass Has a Point: Fiona from Herrington Hotels is portrayed as a Corrupt Corporate Executive and Upper-Class Twit who makes snide comments about the protagonists' competence and social standing, as well as trying to scam them out of the house for less than its actual worth. That said, there is a ring of truth in what she says, as throughout the series Allison & Mike repeatedly shown themselves to be completely out of touch with both the professional realm and the aristocratic, as well as way in over their heads trying to restore such a large and dilapidated building.
Nightmare Fuel: The little plague girl. And they don't try to pretend she isn't terrifying.