In this masterful study of society, Austen seems to reserve much of her scorn for the character of Mrs. Bennet. Austen wastes no time in the first chapter in introducing her as:
...a woman of mean understanding, little information, and uncertain temper. When she was discontented she fancied herself nervous. The business of her life was to get her daughters married; its solace was visiting and news.
Thus Mrs. Bennet is presented as a woman who is obsessed with getting her daughters married. She is shown to be so focussed on this that the actual nature of the men in question appears to be forgotten, exemplified in her delight in Wickham as a son-in-law. Likewise she is shown to be a woman with little understanding of how to behave properly in society. Poor Elizabeth and Jane are constantly embarrassed by their mother's inappropriate comments in society and schemes to try and get them married off, such as when Mrs. Bennet insists that Jane goes to Netherfield on horseback because it "looks like rain" and therefore she will have to stay the night.
Mrs. Bennet is also shown to have a negative influence on Kitty and Lydia in particular, who are allowed to run around without discipline or moderation, acting as flirts and with little regard for others. As Lizzie says to her father when she appeals to him to not let Lydia go to Brighton with the militia, Lydia is in danger of being "beyond the reach of amendment" and "the most determined flirt."