There are the blinders we put on ourselves, and there are those put on us by others. Pride and Prejudice takes on both kinds, unpacking the way identity, motivation, and belief can become grounds for self-deception or deceiving others. According to the novel, the hardest kind of deception to undo is necessarily self-deception – even after secrets are revealed and hidden manipulations are out in the open, it is the lies we tell ourselves that prove the hardest to let go.
The novel's characters are so conditioned to accept the kind of behavior dictated by good manners at face value that they make natural victims for outright liars like Wickham.
The reader is given a hint that Elizabeth will eventually become a much more nuanced judge of character through the deeply empathic and connected way she is able to read her sister Jane when no one else can.