The part in the book (and the movies) when Mrs. Bennet asks Mr. Bennet to force Elizabeth to marry Mr Collins, only to have him turn around with this line:
"An unhappy alternative is before you, Elizabeth. From this day you must be a stranger to one of your parents. —Your mother will never see you again if you do not marry Mr. Collins, and I will never see you again if you do."
When Elizabeth relates Mr. Wickham's tale of woe to Jane, Jane will not believe that Mr. Bingley's dear friend Mr. Darcy would be as cruel as described, and attributes the whole thing to a misunderstanding between the two men. Jane suggests that "interested people" have misrepresented Wickham and Darcy to each other, prompting a teasing reply from Elizabeth.
The scene at Netherfield where Mr. Darcy is trying to write a letter to his sister and his Clingy Jealous Girl Caroline Bingley constantly interrupts him to compliment his handwriting, the evenness of his lines, observe how fast he writes, or add her own message to his sister... while remaining completely oblivious to her target's determination to ignore her as best as he can!
There's also the scene where Mr. Collins proposes and accepts Elizabeth's answers without her responding. She tries to turn him down gently, but he's not worried. He's heard that some women turn down proposals they plan on accepting. Sometimes even three times. It takes quite a while for her to convince him she's not going to marry him.
Elizabeth is relieved when the militia leaves town and begins to hope "by the following Christmas, [Kitty] might be so tolerably reasonable as not to mention an officer above once a day, unless, by some cruel and malicious arrangement at the War-office, another regiment should be quartered in Meryton."
The book's best piece of Lemony Narration comes when Elizabeth runs into her least favorite person, Mr. Darcy, during her walk through Rosings Park: "She felt all the perverseness of the mischance that should bring him where no one else was brought; and to prevent its ever happening again, took care to inform him at first, that it was a favourite haunt of hers. How it could occur a second time, therefore, was very odd!"
Mr. Darcy's first proposal, in its way, is hilarious. The fact that he went in there, laid down a laundry list of highly insulting reasons why proposing to Elizabeth would be a terrible mistake and a disgrace, and then still fully expects that she's going to say yes! Not only that, he accuses herof being uncivil when she is consequently quite chilly in declining. (He, of course, is just being honest.)
While discussing the sad affair of Bingley and Jane, Aunt Gardiner suggests that young men like Bingley are flighty in attraction. Elizabeth assures her that Bingley's feelings were most sincere, because he was starting to offend people by ignoring them in favor of Jane. "Is not general incivility the very essence of love?"
After obtaining Mr. Bennet's consent for the marriage, Elizabeth informs him that it was Darcy and not Mr. Gardiner who saved Lydia. In his typical flippant fashion he is delighted with this news:
"Had it been your uncle's doing, I must and would have paid him; but these violent young lovers carry everything in their own way. I shall offer to pay him to-morrow; he will rant and storm about his love for you, and there will be an end of the matter."
Lydia and Wickham's imposition on the rest of their family. First, she has the brass nerve to ask Elizabeth (the new Mrs. Darcy) for money. Though of course Mr. Wickham could never call on Pemberly, they did stay often at Netherfield whenever they had to find new lodgings (which was often) and so outstayed their welcome that Bingley would actually talk of, maybe, giving them a hint to leave.
Georgiana, though she quickly came to love Elizabeth as a sister, was at first astonished to hear the "lively, sportive" way that she spoke to Darcy—wives can take liberties with their husbands that their little sisters cannot.
The 1940 Film
The early line: "My goodness, what a hullabaloo!"
Mr. Bennett casually suggesting to his wife that they should have drowned some of their daughters at birth. This is what happens when you hire Aldous Huxley to adapt a book.
The 1995 Miniseries
The infamous bit when Darcy dives into a lake and thus spawns the 'wet shirt' fetish. That itself isn't the funny part; the funny part is when he comes face to face with the (at the moment) unrequited and unexpected love of his life, basically half naked by the standards of the time and dripping wet. The awkwardness is hilarious; Elizabeth's even Distracted by the Sexy for a moment or two! Enjoy! -> https://www.youtube.com/watch?v=hasKmDr1yrA
Followed by Elizabeth standing in frozen horror for a few seconds before declaring that they must leave at once.
Darcy's sarcastic expression and rolling of the eyes when his conversation with Elizabeth (and Colonel Fitzwilliam) is interrupted by Lady Catherine.
Elizabeth providing occasional riffing on Darcy's letter. "I look back with regret on only one aspect of my behavior in this matter..." "Oh, really? Astound me."
Any time Caroline says something cutting about Elizabeth, and Darcy manages to turn it around and use it to insult Caroline.
"Other way, Mr Collins!" Poor Lizzy...
When Bingley is gushing over Jane after first meeting her, Darcy replies with a gruff "she smiles too much."
Charlotte details her married life to Elizabeth. She encourages Mr. Collins to be in his garden; the fresh air is so healthy. She encourages him to be in his library as reading is good for the mind. She encourages him to call upon Lady Catherine... so it turns out that they hardly spend more than a few minutes of the day together at all. She can bear the solitude quite well.