These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
No one thought of Saffy/David though, despite that being just as much of a crack pairing, so cue surprise from the fandom when the pairing was canonised in Rose's December 2013 blog post.
Draco in Leather Pants: Some fans believe Bill Casson to be an in-universe example of this trope, as everyone (except Rose) studiously overlooks his faults and misdemeanors - most of the time because he's so "charming" and "hawt," Eve especially out of them all.
Ensemble Darkhorse: Rose in Saffy's Angel, to the extent that later she got her own book (Forever Rose) told from her point of view.
Tom/Rose when it comes to the other pairings in the series.
Fan-Preferred Couple: Tom/Rose. Pairing her with David causes consternation within the ranks, but so far that doesn't happen in the fandom - where Tom/Rose is the pairing that everyone hopes wins and gets together on her blog or however McKay plans on getting them together.
And she'd better, or cue fan mayhem and hysteria, which hasn't been helped since the addition of Meg, a new character on the blog, who is apparently close to Tom. Cue Tom/Rose fans hating her.
Harsher in Hindsight: Saffron's colour being left off the colour chart in Saffy's Angel and her denials that Bill "is not her father" seem much darker in hindsight after the revelations in Permanent Rose that Bill is indeed her father and has hidden that knowledge away from her and Eve, her mother's sister for so long.
Iron Woobie: Rose is starting to show signs of this at her Twitter account, especially when fans ask about Tom. It's obvious how much she loves him, although it appears she is beginning to give up on him, declaring that he and Meg are "meant for each other" in answer to a comment as if in an attempt to hide her pain over the relationship.
Nightmare Fuel: In-universe, as Kiran's stories frighten Rose dreadfully.
Portmanteau Couple Name: Because of a fan forum at Fanfiction Dot Net, Tom/Rose has been christened "Permanent Tom," while Bill/Eve has become "Evill," while other known couple names like "Maddy" for Michael/Caddy was also mentioned.
The Scrappy: Bill Casson and David get some flack from fans, making them the least-liked characters in the fandom. Meg, Tom's friend, has become this since her entrance into the Blog where it looks as if she is trying to get in between Tom and Rose's relationship.
Shipping Goggles: Fans put them on whenever a hint of Tom and Rose interaction comes up, whether it be in the books, her blog, or on Twitter.
Why Would Anyone Take Him Back?: Eve and Bill Casson. Even though he's cheated on her twice first with her sister and then with Samantha, she still takes him back.
The Woobie: Saffron. A brief overview of her life is this: her grandfather suffers a heart attack bringing her back to England from Siena, she only learns that she is adopted at age eight, which immediately causes her to lose her bonds with her family, her father doesn't reveal himself to her until she is at least fifteen in Permanent Rose, and this is beginning to show up with her various troubles with guys.
Rose in Permanent Rose, especially the passages in the book indicating her longing for Tom. Somebody give the girl a hug!