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.
Freud Was Right: It pains Fanny to see Mary Crawford riding the horse Edmund once established as solely for Fanny's use...
The necklace scene. Fanny has two possible chains for her cross—one from Henry and one from Edmund. Henry's doesn't fit in the designated hole. Edmund's fits just fine.
Hilarious in Hindsight: Mary Crawford blames Fanny for her brother eloping with Maria Rushworth, saying no harm would have been done if she had just married him, and his relationship with Maria "would have all ended in a regular standing flirtation, in yearly meetings at Sotherton and Everingham." A few decades later, it's like Anne Bronte read that alternate ending, wondered, "What If?", and wrote The Tenant of Wildfell Hall to answer the question.
Les Yay: Fanny/Mary Crawford — much more subtle than Emma/Harriet but definitely there.
Edmund: Well, Fanny, and how do you like Miss Crawford now?
Oh so much between Frances O'Connor and Embeth Davidtz in the 1999 movie, at least for as long as Fanny isn't a serious contender for anyone's hand in marriage.
Macekre: Some people feel that various adaptations of Mansfield Park itself, notably the 1999 movie and the 2007 film, are vile travesties of the book, based on statements by filmmakers in each case saying that they didn't find the character of Fanny very interesting. Other people feel that the adaptations are an improvement, on account of Fanny becoming less of an Extreme Doormat.
Misaimed Fandom: Sorry, Jane, but some readers still judge Fanny Price and Mary Crawford by their first impressions.
Ship-to-Ship Combat: Mockingly between Jane and Cassandra Austen, according to their niece Louisa Knight.
They Just Didn't Care: The cast of Lover's Vows, with the exception of Mr. Yates, is concerned with the flirtations and betrayals which occur under cover of "rehearsals," rather than any serious attempt to produce the play.
The first of the early warning signs that Mary Crawford is a Bitch in Sheep's Clothing seem less blatant when looked at through modern eyes: She makes anopen criticism of her uncle, a highly disrespectful action in that time. Also, Edmund is opposed to the play on many grounds - but one of them is the 'indecency' of his sisters being on stage in front of an audience, something we would not bat an eye at today.
Except that, no matter how normal acting would be... it is still an excuse for Maria flirting with another boy than her fiance, right in front of him. This is still pretty mean-spirited by many current peoples's standards, and Fanny's disapproval on this ground is completely justified for those who think of it. Doing something close from flirting and playing on a way that could cause a bad reputation is something that can easily cause Big Brother Instinct.