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.
Never ask whether the dragons are measured in feet or meters. Oddly enough, there's a composite scale going around that most of the role-players accept quite readily.
Rapidly approaching this concerning Todd McCaffrey's books, divided mostly between fans who say "Eh, they're not that bad" and those who consider them ascended fanfiction.
Complete Monster: While most of the antagonists are at least somewhat nuanced, there are a couple who would seem to qualify as this: Fax and Avril Bitra are probably the standout examples. Others, like Stev Kimmer and Thella, start out more as JerkAsses but gradually devolve into this.
"Funny Aneurysm" Moment: In All the Weyrs of Pern, chapter 11, in a light-hearted exchange, Golanth boasts that "No feline would challenge me!", with F'lessan agreeing. Not so funny at the end of The Skies of Pern...
F'lar actually thinks to himself that he "might as well call it rape" when he has sex with Lessa and their dragons aren't involved (this is before they actually fall in love). He's vaguely troubled by this but not overwhelmed with guilt or anything, and it doesn't seem to occur to him that maybe he should stop having sex with her unless she actually wants it. He just figures he's pretty good in bed and he'll get her to come around eventually. Notably, it's not actually important that F'lar actually conceive by Lessa, and the Weyrleaders and Weyrwomen are not required to sleep with each other, so he was raping her for his own pleasure.
F'lar never says that Lessa was unwilling, though- she wasn't responding wholeheartedly. It's possible she was willing, but wasn't exactly putting a lot of effort into the act.
The way the highborn characters treat lower-ranking individuals is also pretty appalling. Lessa is bad-tempered and judgmental to the point that she nearly causes a political crisis by demanding that an insult be punished; Jaxom generally ranges from thoughtless to downright obnoxious in the way he treats commoners. Both do mature at least a bit over the course of the series.
There's also some Values Dissonance in how the disabled are treated — in MasterHarper of Pern, Robinton fathers a mentally disabled child. The child's mother urges him to go find peace and happiness by paying attention to the other boys, and not worrying about his so very disappointing retarded kid.
The drudges in general are often treated pretty badly. Given that most of them seem to be mentally disabled, this carries Unfortunate Implications.
Drudges are the equivalent of servants- most Holderfolk consider them not much different from furniture. Despicable, but not Unforutnate Implications. The reason most are mentally disabled is because no-one is a Drudge unless they have no choice - the mentally disabled can't do anything else.
Word of God on how Impression and sexual orientation work implies that riders who aren't 100% heterosexual are barred from leadership positions in the Weyr, as only heterosexuals are supposed to Impress bronze and gold dragons. (Of course, at the time McCaffrey began the series, including any roles at all for non-heterosexuals was considered progressive.)
The Woobie: Menolly. Early on, very much so. After she comes out of her shell, she's a far more assertive character that only fools would think of messing with.
Jerkass Woobie or Iron Woobie: Lessa. You really can't blame her for being so harsh and temperamental considering her family was massacred, she'd hidden as a slave in her own home for ten years, and the main reason she decided to try for Weyrwoman was because she had no clue what she'd do after getting revenge on Fax. When F'lar actually asks her about it, she realized that "she hadn't thought that far before."