intellect!

Mrs. B. is ALWAYS in a tizzy about something because she is so air-headed. She has NO intellect and so has no long-term interests (reading, charity work, etc.) other than her daughters' marriage prospects. Anything that is new catches her attention (hats, men, fashion, gossip) because it creates no demand on her brain, only on her senses. [Lydia is so like her mother in this respect.] Mrs. B. is always caught up in the NEWNESS of things and so they excite her.

Mr. B. is an intellectual (too much so to the neglect of his family). Twenty-some years' of Mrs. B's constant yammering about trivial things inspire no excitement in him. He has suffered her asinine comments for so long that they don't even excite him to irritation. His responses are always sardonic and patronizing. Nothing she says can ever truly interest him or excite him because she has no depth and he considers himself a deep-thinker. His contempt for her (however glibly he attempts to conceal it) is equalled only by his contempt for himself in having married her. That is why I think he can never really despise her...she is who she is, and HE made the mistake in marrying her.