Lizzy perhaps also is the most likely of the Bennet girls to not do what her mother tells her to do; and likely to tell her mother when she disagreed with her. She won't marry Mr Collins even though her mother threatens, at the very least, never to speak to her from that day. So her being headstrong and outspoken in character, and I would imagine often disagreeing with her mother's silliness, probably didn't endear her in her mother's eyes !!