] Mr. Bennet seems to take pleasure in his wife's disappontments. I always thought that he must really dislike his wife if he hopd that the ball was less than she hoped it to be ...

Mr Bennet knew that if Bingley were attentive to one of the girls AND if Bingley seemed really & truly as eligible a man as prior reports had indicated, then Mrs Bennet would continue all her scheming. Perhaps Mr Bennet simply wanted to remove one topic from Mrs Bennet's list of things to drone on about. :-)