One thing I have noticed is how often (some) critics will define Darcy's behavior at the beginning of the novel entirely negatively, forgetting that Elizabeth (who believes at this point that she dislikes him and who has condemned him for various perceived faults) actually defends many of Darcy's actions in the first few chapters. A good example of this is at the Netherfield ball when Mr. Collins approaches Mr. Darcy.
"You are not going to introduce yourself to Mr. Darcy?" [Elizabeth said.]Mr. Collins does approach Darcy. The result is Darcy's "astonishment at being so addressed." The conversation (or monologue by Mr. Collins) ends when Darcy "made him a slight bow, and moved another way."
"Indeed I am. I shall entreat his pardon for not having done it earlier. I believe him to be Lady Catherine's nephew. It will be in my power to assure him that her ladyship was quite well yesterday se'nnight."
Elizabeth tried hard to dissuade him from such a scheme, assuring him that Mr. Darcy would consider his addressing him without introduction as an impertinent freedom, rather than a compliment to his aunt; that it was not in the least necessary there should be any notice on either side, and that if it were, it must belong to Mr. Darcy, the superior in consequence, to begin the acquaintance. -- Mr. Collins listened to her with the determined air of following his own inclination.
To modern (American) minds, Darcy is just rude. Why shouldn't Mr. Collins speak to whomever he wants? However, in Darcy and Elizabeth's world, Mr. Collins is completely out-of-line.
To modernize it, imagine you attend a dinner party put on by friends. The dinner party is intended to be relaxing, fun, a good time for all. But during the evening, this one guy keeps approaching people, forcing his business cards on them, and buttonholing them into buying life insurance.
This is EXACTLY what Mr. Collins is doing. He doesn't approach Mr. Darcy out of goodwill but out of a desire to aggrandize himself. And Elizabeth is rightly mortified.
Note, too, that although she is partly mortified by the ridiculousness of Mr. Collins' conversation with Darcy (not reported here), she is mostly mortified by his decision to introduce himself. That is, despite Elizabeth's egalitarian impulses, she still accepts, even practices, the routine civilities of her society.
The appropriate course for action would be for Mr. Bennet, who has already officially met Bingley and Darcy, to do the introductions: "Mr. Bingley, Mr. Darcy, I would like to introduce my cousin, Mr. Collins. I believe Mr. Collins has some acquaintance with your family, Mr. Darcy."
This is forestalled partly by Mr. Collins' smugness but also by Mr. Bennet's laxity. But the inappropriateness/wrongness of Mr. Collins' actions are not disputed by the characters.
What I think is in dispute is Darcy's reaction, and this is where personality (and possibly pride) come into play. If Darcy were a pure social extrovert like Bingley, he would be able to smooth over Mr. Collins' social infraction with an easy, blithe remark. But Darcy doesn't think that way. When Mr. Collins approaches him, Darcy's brain (which is wholly occupied with Elizabeth at this point) does something like this: Why is this guy talking to me? Why am I having this conversation? I shouldn't have to have this conversation! Go away! He isn't going away. I gotta get out of here. And he does. Darcy's "pride" is in not thinking beyond the temporary, annoying invasion into his space.
But even Elizabeth admits Mr. Collins invaded Darcy's space.