I'm not sure it's always the contestants that make the experience of the quiz less warm or likeable than other programmes (whatever the intellectual content) . I think the presenter is often awkward and lacks charm and spontaneity. She's like an interviewer who asks a small talk question at the start but doesn't really want to hear the answer, and it shows. But as i said, i'm not a fan of hers. Interesting though that some are losing enthusiasm during this series (the only one I've actually watched)