Reading Goodreads reviews, especially 1-star ones, I realise, yet again, that there are many ways of engaging with texts. Some readers always seem to be in "reading on the sunbed" mode. Reviews of short story collections not uncommonly contain phrases like "I don't usually read short stories". Lately I've been reading (or listening to) far more genre novels, more novels where immersion is encouraged, so I thought I'd go over the basic questions again, as if I were in discussion with Goodreads reviewers.
Must you like the novel's characters? - it's common to come across comments like "The main character is irritating and pathetic". I've some sympathy with these views. After all, you the reader will be spending many hours with the characters. If you'd hate being stuck in a room with them in real life, why be stuck in a book with them, especially if you're in "holiday reading" mode. But they're characters, not real people.
Must you find them interesting? - you may not like a Martin Amis hero, but they may be interesting - not least because they're unlikable, they're unlike you. It's better for characters to be nasty than plain boring. Beside, the characters may not be the main issue of the book.
Must you empathize/identify with them? - perhaps you've experienced some of the feelings they have, even if you don't like them characters. Safely between the covers you can re-experience those emotions again, or even experience emotions you've not lived through yourself. A good writer might make you feel sorry for an unsympathetic character.
Must they not be repulsive? - it's one thing for characters not to resemble you in many ways (to like Mozart while you prefer Bach for example), it's quite another for characters to hold views on gender or race that you stridently disagree with, especially if the characters aren't punished. But maybe the characters are interesting.
Do you have to believe the characters? - suppose the characters are not like anyone you've met or can imagine? Suppose they fail the Turing test? Well, it's only a book. The plot, the thoughts or the style may matter more than the characters. Maybe it's SF.
Do you have to like the author? - Do you check before you start reading their book? Suppose there's no way to find out about the author? Suppose you like the characters anyway?
One advantage of short stories is that they don't test the readers' emotional or intellectual endurance. And a persona in a poem is rarely subjected to such questions.