How important is it to you that fictional characters (in books/movies/TV) be likable?

I’ll mostly be talking about books because the examples that led me to ask this came from books, but it can be about anything.

I’ve often seen negative reviews of a book cite the fact that the characters (protagonists) were unlikable and that was a major factor in why the reviewer did not like the book.

Rabbit, Run is a good example of a book with an extremely unlikable protagonist. This guy, Rabbit, is the worst. The book worked for me because it’s clear that A) we’re not supposed to like Rabbit, and B) I can’t help but find it fascinating to get inside this guy’s mind and see how the people around him are affected by his behavior.

Clearly if I’m meant to like a character and I don’t like them, it makes the book hard to read for me. Yet if the characters are not supposed to be likable, they at least need to be relatable or interesting enough that I want to know what happens to them. Walter White in Breaking Bad becomes less and less likable as the series progresses, but watching his transformation into a villain is what makes the series enthralling.

How likable do characters need to be for you? Can you think of a book or TV show or movie where the main character(s) is (are) unlikable (for whatever reason) that you still enjoyed?