One advantage of not being in academia is that I can admit that I simply hate certain characters. That is so unsophisticated, but often our reactions to what we read are grounded in nothing more (or less) than we dislike key characters. It is fine to dislike the antagonists in a novel, but when the reader dislikes the main characters or cannot sympathize with (or even understand) the actions of the core characters, then problems set in. Sometimes the reader can appreciate a look into a world that "there but for the grace of God go I." Though personally I wonder whether this is just a form of literary slumming. I generally don't like books written by middle class authors about lower class characters (where these characters are front and center throughout the novel), since I just don't think you can avoid issues of misrepresentation. While I happen to think George Walker has really moved a long way from his working-class roots, he does have that grounding.
Even if one is sticking to novels that are about people in the same class, there is the issue of whether the reader can ever appreciate characters that act very differently than he or she would (or at least how the reader imagines him- or herself acting in those situations). So for instance, it is almost impossible for me to relate to stories where the main characters get drunk all the time or take boatloads of drugs -- or spend all their money stupidly like so many of the artistic types Barbara Comyns was writing about. I do consider it a minor moral failing to lose control to that extent, and mostly I find these kinds of stories boring. That is the main reason it took me so long to get around to reading any novels written by the Brat Pack. Now in the better novels, there is some ironic distancing where the main character knows he (usually its a male) is acting badly* but goes and does it anyway (and there may or may not be some underlying trauma that explains why they have been driven to drugs or what have you). This is seen not only in McInerney's Bright Lights, Big City, but pretty much all the works by the Canadian author, Russell Smith. When I am in a good mood, I can read these stories with equanimity, since I know for sure I will never go down that rabbit hole. When I am in a bad mood, I find these characters weak and somewhat boring. I may dislike them to some extent, but I generally would not hate these characters just for being weak. (Though if the author is trying to hard to rope me into tolerating or even forgiving bad behaviour through the use of first-person or even second-person (!) narration, then I might be more resistant.**)
There is no question I don't like books about weak-spined characters, and I've written about that here to some extent. I found it a huge drag to read Maugham's Of Human Bondage and also Vargas Llosa's The Bad Girl, which at least was shorter. I suppose in both those cases, I did hate the female characters that treated their erstwhile boyfriends so badly.
I definitely don't like characters that treat others badly, even if it is in a comic vein. As it turns out, I have written more than I remembered on such "detestable" characters. Here I am trying to focus on when it is the main character (that the reader identifies with by default) that is acting so badly. I have such mixed feelings about Ignatius J. Reilly from Toole's A Confederacy of Dunces and Ed from Vandergaeghe's My Present Age. They are complex, intelligent characters, but they just treat people so badly essentially because they are such egoists that nothing else ultimately matters but their own desires or intellectual hobby horses. Maybe I dislike them so much, since it is something I have to fight in my own life, only sometimes with success.
I actually stopped reading Donleavy's The Ginger Man, since in addition to being such an over-the-top egoist, the main character was a wife-beater. I simply could not countenance a supposedly comic novel with such a loathsome chracter at its heart. (He's way beyond the "zany" characters that I would avoid like the plague in real life but can somewhat tolerate in fictional form.) I've kind of blocked out major parts of Cassandra at the Wedding, but as I recall, Cassandra is driving across the country, trying to disrupt and ideally block her twin sister's wedding. I certainly didn't like her, but mostly I pitied her, since she was in the midst of some kind of mental breakdown apparently. I honestly can't remember the denouement of that novel, though I'm pretty sure the wedding did go on.
To add to this list, I have discovered perhaps another appalling character, perhaps just one notch below Sebastian of The Ginger Man: Harriet from Iris Owens' After Claude. She is a lazy, clingy sponger who is also mean-spirited towards her current and former friends. She clearly has something wrong with her mental facilities, since she thinks that her friend's problem with her crashing in her apartment is fundamentally due to sexual frustration, so she arranges for a stranger to come and try to rape her while she is sleeping (yes, this is actually a plot point, and she gets all upset when her intentions are "misunderstood"). She also is about to be thrown out of another apartment, by a fed-up "boyfriend," so arranges to have the locks changed and bars herself in for a while. I can't remember ever wanting harm to come to a major character as much as I did with her. I outright hated her, and I was glad that she was going to end up joining some creepy cult by the end of the novel. Good riddance. The whole novel upset me, and not really in a good way. I'm not at all surprised that in real life Iris Owens was an "interesting" but difficult woman who was not on speaking terms with a number of her former friends. Spare me from such intelligent and interesting people...
* Along those lines of being turned off by an author trying to seduce me into being complicit with bad behaviour, I will admit to being awfully alienated from the narrator of Adiga's The White Tiger and pretty much all of Mohsin Hamid's characters.
** Actually, there is another somewhat well-worn trope with authors making a main character deeply conservative, or even racist and/or sexist, either to make the reader aware of his or her own prejudices or to somewhat explain (if not forgive) where these characters are coming from. I'd say it is a mixed bag how well this works. In Marlene van Niekerk' Triomf, pretty much all the characters are white-trash Boers, and it is basically Deliverance in suburban Johannesburg. I'm not sure what she was really hoping to achieve, but it was a pretty ugly novel. It is far more unsettling encountering an intelligent, somewhat cultured but very racist narrator in Ivan Vladislavic's The Restless Supermarket. I've been meaning to blog separately on this, so I won't write too much here, but the narrator is a bit hard to stomach at times, though I certainly never loathed him, as I did some of the other characters I discuss here.