Obviously, since the novel is the story of Pip's maturation, the theme of growth/change are all important.

-As Pip visits Miss Havisham during his preteen and teen years, his views of society change.  Miss Havisham and Estella make him feel that he is not good enough by society's standards, thus planting the seeds of discontent with his situation in life. This change in his self-image causes him to become judgmental of Joe and other characters from his hometown.  In contrast, when the reader first meets Pip, he worships Joe and looks up to him.

-When Pip goes to London to become a gentleman, he learns the difficulty of managing money, fitting into a class-focused society, and choosing confidants wisely.

-Finally, after Pip learns the identity of his benefactor and begins to see the errors of his ways, he returns to those whom he knows he can trust such as Biddy, Joe, and Herbert.

The theme of suffering, not just by Pip, but by almost all of the novel's major characters, illustrates Dickens' theory that people must suffer to mature and to find satisfaction in life.  Suffering for some of the characters is a consequence of their poor choices.