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.
Anvilicious: The text emphasizes its message on the importance of yielding to persuasion by brutally physically punishing Louisa Musgrove.
Esoteric Happy Ending: Anne learns near the end of the book that Mr Elliot is rather an unpleasant person, and is trying to ensure his inheritance of Sir Walter's title by any means necessary. By the end of the story, he... is closer to his goal, since Sir Walter and Mrs Clay are no longer a couple and thus won't produce an heir. Anne and her friends get their happy endings, but the inheritance is still destined for someone rather awful.
Rule Abiding Rebel: Inverted, Anne believes she would have been happier marrying Captain Wentworth from the beginning even if he had never made a penny, and the narrator points out that two unsuitable young people in love are usually able to get married, never mind two mature people with one independent fortune between them.
Ship-to-Ship Combat: In-universe - Charles Musgrove is a Louisa Musgrove/Captain Wentworth shipper; his wife Mary is a Henrietta Musgrove/Captain Wentworth shipper. Things almost get ugly between them over this. There were deeper implications. Mary really didn't want Henrietta to "throw herself away" on country curate Charles Hayter. It is, after all, very inconvenient to be "giving bad connections to those who have not been used to them."
Real women must yield to persuasion, regardless of the value of the counsel, decides Anne towards the end.
"I must believe that I was right, much as I suffered from it, that I was perfectly right in being guided by the friend whom you will love better than you do now. To me, she was in the place of a parent. Do not mistake me, however. I am not saying that she did not err in her advice. ... But I mean, that I was right in submitting to her, ... and if I mistake not, a strong sense of duty is no bad part of a woman's portion."
Or, alternatively, female/family attachments matter before romantic ones (seeing as her boyfriend was giving her 'persuasion' of exactly the opposite nature, her dilemma wasn't whether she yielded to persuasion, but to whose.)