I don't have to like the protagonists. I need to care about what they do. I've taken a few literature courses and some of the most irrepentant, boring, flotsam-like characters reside in the Modernist stories, IMO. As ever, I'm thinking about Sister Carrie. I didn't care what happened to Carrie and her men. They were nothing. Despite success, despite tragedy, despite situations that might have driven a dramatic plot, they stagnated. I didn't care about them or about what they did. I only ended up despising the lot of them (Hurstwood least of all but still, an unrealized potential).

The characters must engage me or the book's worthless. I have to care.