As my husband said when I asked if he had read 'War and Peace' (which I enjoyed): "I asked myself whether I would care if, in the next chapter, every character developed the purple spotted plague and died. The answer was no. So I stopped reading." There are some characters in 'Game of Thrones' that take me that way: Sansa, Littlefinger, that stupid boy king, for example. On the other hand, I find myself caring what happens to Bran, Arya, Tyrion, Brienne, Jon Snow and Sam. I know many people stopped reading when the character they liked best went down.
Stephen Donaldson is another writer whom I find 'good in parts'. His prose is a delight. The giants are a marvellous creation. His landscapes sing. But Thomas Covenant....if I want to read an annoying main character, I'd prefer Hannu. Covenant rouses in me the impulse to pick him up by the scruff and shake him out of his self-indulgent whining. It quite spoils the story for me.