"No -- I cannot talk of books in a ballroom; my head is always full of something else."

"The present always occupies you in such scenes -- does it?" said he, with a look of doubt.

"Yes, always," she replied, without knowing what she said, for her thoughts had wandered far from the subject,...

I had to laugh at this. (Bold emphasis is mine, italics is JA's)... We know Darcy is clever (and seemingly attending to what she's saying) so I am sure he catches this... Had she not brought up Wickham, it would be interesting to know what he said next as I think he's trying quite hard to please her and be friendly. He's smiling and making conversation, which up to now isn't exactly his forte! I just thought the complete contridiction was hilarious (as is a lot of EB's logic at the moment, talk about being blind to faults!)