Why do you need to like the protagonist?

Do you need to like the characters to like the book?
Actually, let's go back a step...

DO you need to like the protagonist in a book?

The reason I'm asking is because I was speaking at a book group the other week and we had a fairly lively discussion about whether we ended up rating a book less highly if we didn't like the protagonist. I was firmly in the camp of not needing to like the protagonist to enjoy a book and to rate it highly; others around the table felt that if they didn't warm to the protagonist, they didn't enjoy the book and so didn't rate the book so highly.

Maybe I'm odd (it has been said to me, many a time and oft), but to me, how the protagonist deals with what is thrown at them interests me more than needing to like them. In life, people are complex, with bits of their character that you like and bits that you don't. I wouldn't feel less interested in whether a protagonist got out of a horrible situation, just because he or she wasn't someone I would like to spend time with. I mean, I don't know that I could spend much time with James Bond without being really irritated by him, but that doesn't mean I don't enjoy a good Bond story.

You see, to me, that's the key bit - is the story good? And are the characters believable. Not necessarily nice, but believable. When things get thrown at them, do they react in a way that's credible?

But it became apparent at the book group, that not everyone sees it that way and that if the protagonist is someone they didn't like, they didn't like the book.

What do people on here think? Do you mind if the protagonist is annoying or unlikeable? Do you like your characters more flawed and complex? Or maybe, you root for the antagonist?
Let me know in the comments?