Because Great Expectations is narrated by its protagonist, its mood is strongly aligned with how Pip "remembers" events. The reader is intimately connected with Pip's perceptions, private thoughts, and feelings. The mood of the reader becomes intimately connected to the condition of Pip's inner world, as he is such a sympathetic character. When injustice is done, it makes the reader feel outraged; when he feels joy, the writing provokes an echo of that in the reader.
The mood of this book is also often quite reflective, as Pip wistfully looks back on the events of his life and considers how he could have behaved more ethically or more kindly. Pip often thinks about the possible outcome of situations if he had acted differently, or if he had known what might happen before making a particular choice or believing a particular lie. The reader is able to understand and echo the regret and nostalgia Pip feels because of how closely the narrator ties his trajectory of development to his own feelings; a lot of this book gives the reader a sense of "if only!" There are also instances in the book where the mood is actively frightening, most often when the plot deals with the jilted bride Miss Havisham in her "rotting" house, or either of the two convicts who variously trouble Pip. When Pip describes the dim and spooky moors, with their mists and their creeping damp, the reader feels his childish unease. The stark imagery of Satis House, in which Miss Havisham crouches in the darkness like an insect, is also very evocative for the reader, making them feel pity and disgust for her in equal measure.
Early in the novel, the mood varies from wild excitement as Pip begins to grow into adulthood, fall in love, and explore, to deep despair as he realizes the limitations the social class he was born into places on him. These two "poles" of feeling recur over and over, as reader and Pip together have their hopes raised and their expectations dashed. Because it's captivating and provokes curiosity, this ebb and flow is also a very common characteristic of mood in originally serialized novels like this one.
The book ends optimistically, if not very clearly, as "mists rise" and Pip and Estella reunite and walk into their future together. The satisfying end to their love story belies the uncertainty of their future, but the reader is comforted in the knowledge that at last, Pip sees "no shadow of parting" from Estella.