Characters—gotta love 'em. Or do we?

Do we have to love a book's main character? What happens if we despise the hero/heroine?

I just read a blurb for Zoe Heller's new book, Believers. Critics are praising it up and down, though some find the characters unlikable ... can’t relate to them ... even find them NASTY!

So, back to my question. Can we enjoy a book without liking its characters? Love the book, hate her—as in Serena, another recent book with a heroine no one can stand.

How about Emma—Jane Austen’s masterpiece? Even Austen knew her dear readers would have trouble liking her control-freak-of-a-heroine. Then there's Lolita, featuring one of the most dastardly heroes in all of literature? Humbert Humbert is surely enduring if not endearing—and the book is considered one of the great works of the 20th century.

Still ... it’s hard to get into a book when characters are unlikable. Am I alone? Probably not.

Questions for Book Clubs

1. Can a bad character ruin a good book? 
2. How do you begin most of your book discussions—by talking about the characters?  And if you don’t like the main character...where does the discussion go? Does it peter out?
3. If a character is unlikable, is it intentional on the part of the author? To what end?