Accidental Aesop: Respect your partner's desires in a relationship and if you can't understand them, rip the bandaid off and break up before it gets serious. John tells Lenina he wants their bond to have meaning, which is why he doesn't want to just sleep with her. She doesn't listen and keeps pressuring him. Tragedy ensues.
Accidental Innuendo: At one point, in discussing Bernard, Lenina and Fanny comment that he is "so small" (emphasis in original). Of course, in context, it is clear that they are discussing his height. To some readers, it can appear that they are talking about his length.
Are the people in the civilized world exploiting John by parading him around like a rarity or are they showing their hospitality the only way they know how and trying to introduce him to the ways of their world? Huxley would probably argue the former. The real answer is more likely they aren't exploiting him intentionally, but John (more or less rightfully) sees it that way because of his different cultural outlook.
John's confrontation with Lenina can be read a few different ways. Is John's insistence on chastity a toxic neurosis that leads him to unjustly attack Lenina, or is John right to refuse Lenina's advances because John sees Lenina as a sexual harasser with no understanding of boundaries, consent, and the deeper intricacies of a romantic relationship (since those don't exist in the civilized world she lives in)? The language he uses ("whore," "strumpet") can make the scene feel less like John is fighting off a sexual harrasser and more like he's slut-shaming and abusing Lenina. John's framing as being in opposition to the dystopia might suggest that we're intended to see him as being right, but his prior behavior—creeping into Lenina's room while she's doped up on soma to ogle her—casts even this into doubt.
Part of the reason John committed suicide seems to be not just that this world he has been introduced to is so horrible, but also because he felt he didn't belong anywhere: the people in the reservation hated him for having a mother who was part of the civilized world and the civilized world John wished to be part of is shallow, hedonistic, and soulless.
The "Feelie" pornographic film whose simplistic plot is detailed partway through plays pretty openly on racist tropes regarding the savage, animalistic virility of black men, and some probably unintentionally sexist and racist assumptions are made about how women psychologically need to feel pregnant through the use of a surrogate and darker-skinned women need it earlier because they're "born to have babies young." This raises the obvious question of whether or not the World State has actually eliminated sexual and racial discrimination, as it claims, or whether it's been institutionalized and normalized to the point that the world's population no longer notices it... especially since they've been left stupid and ignorant, while actively being indoctrinated against thinking too deeply about it!
Anvilicious: The book wouldn't have been half as effective if Aldous Huxley had been even the least bit subtle in his condemnations of hedonism and eugenics.
Hard-to-Adapt Work: This book has traditionally been regarded as far more difficult to adapt than Nineteen Eighty-Four and other famous dystopian novels. Not only is the book more focused on building the setting than on plot or characters, but that setting also features extreme sexuality, even between minors. An accurate adaptation would verge on vanilla pornography, if not worse. It did get two Made For TV Movies (both with large changes to plot and characters, though the 1980 UK version was slightly more faithful to the novel than the 1998 American version) and a series adaptation on NBC's Peacock streaming service (which was more of a TV drama/mini-series than an actual movie and was about as faithful to the novel as the American TV movie version [read: kept in some plot points, characters, and parts and eliminated others for censorship and artistic license]).
The worship of Henry Ford looks even sillier given the direction of his namesake company and the U.S. car industry as a whole.
The description of in-vitro fertilization years before the world's first test-tube baby was born.
Jerkass Woobie: Bernard wants so desperately to fit in with his happy, carefree society, and can't figure out why he is not happy doing the things that seem to make other men happy. He turns into somewhat of a jackass (by real world standards) once he gets a taste of popularity, but he can't entirely be faulted for trying to follow the shallow rules and values deemed important in his world.
John can qualify as well. His treatment of Lenina is rather questionable, but one can't help feel bad for all he's gone through.
Misaimed Fandom: Some hedonistic fans don't view the Brave New World as all that bad and agree with Mond's belief that happiness should be prioritized over goodness, with some even wishing they could live in that world. This completely misses the point of the book, which is that happiness without goodness—such familial bonds, free-thinking, moral values, respect for others, and love—is shallow, unfulfilling and destructive.
Moral Event Horizon: The government of the Brave New World is firmly established as a Very Bad Thing in Chapter 2, where we see the use of Electric Torture on Delta babies in order to condition them into having an aversion to books and flowers which will stop them from educating themselves or enjoying nature.
Narm: Late into the book, John is wrestling with guilt over his sexual attraction towards Lenina and begins having a sexual fantasy about her. So he throws himself into a thorn bush and then beats himself with a whip. Even if you believe in chastity, this is a hilariously over the top reaction.
Squick: In the casually promiscuous society in which the book takes place, it is considered healthy, even endearing, for young children to sexually experiment with each other. There is also a memorable passage pointing out the more Freudian aspects of breastfeeding, and the descriptions of John's mother.
Huxley himself constantly championed the increasing relevance of Brave New World in interviews conducted near the end of his life. Modern editions often mention on the back cover how many of the book's predictions about the future seem to be coming true, and Huxley himself wrote Brave New World Revisited, a commentary on his own work in which he concludes that the world was becoming like Brave New Worldat a much faster rate than he thought.
For those that are more inclined not to view the Brave New World as villainous, the book provides an excellent speculative example of culture shock or how good intentions can lead to harm.
The Woobie: Poor, poor John "The Savage". As if growing up bullied and ostracized by everyone was bad enough, he ends up despising the very world he thought would be his one salvation. And after being ostracized there too and paraded around like a circus animal, he chooses exile. After the curiosity seekers chase him even there, and after betraying his beliefs in a drug-induced stupor, he is finally Driven to Suicide.