On the advice in this post of thingy, I’ve been reading the book Jane Eyre by Charlotte Brontë. I think it’s a very good book, but in the early going, there’s a character named “John Reed” whom I find astoundingly irritating. Obviously, the character is intended to be this way, but I feel that he is rather too well-written in this regard, and becomes so unpleasant as to impair the reader’s (well, this reader’s) enjoyment of the book.
I’d never thought about it much before, but it’s a delicate balance in fiction to write unlikable characters. You don’t want them to be too sympathetic, obviously; or it screws up the audience’s reaction to them. But if you succeed too well at making them unlikable, people might say “I deal with enough jerks in life as it is”, and give up on the book altogether.
Not that I’d do that with Jane Eyre. It’s quite good.