social expectations

This is rather a large question for this short answer forum. The class system was very rigid and demanding during this era. Much of the "inappropriateness" surrounds class structures of the time although I'm sure some of it still exists today. The novel opens at Longbourn, the Bennet family's estate. Mr. and Mrs. Bennet have five children: Jane, Elizabeth, Mary, Kitty, and Lydia. The family engages in a conversation about Mr. Bingley, "a single man of large fortune" who will be renting the nearby estate of Netherfield Park. Mrs. Bennet sees Mr. Bingley as a potential suitor for one of her daughters. The emphasis here is not about "love" and "happiness" rather than a union born out of money and social status.

Mrs. Bennet and Lydia Bennet provide a lot of examples of incorrect behavior in public. On the other hand, Sir William Lucas is always displaying refined manners. At the scene of the encounter between Elizabeth and Mr. Darcy, the latter is described as behaving like a gentleman, and so is Elizabeth's uncle, Mr. Gardiner. You can also consider the social expectations of women of that time. For example, when Elizabeth walks several miles to Netherfield in bad weather in order to take care of Jane, she is criticized by Mrs. Hurst and Miss Bingley (behind her back, of course).