What does Pip learn about friendship in the novel and how does is it affected by social class

Pip learns that the truest friends do not have to come from the same social class. He also learns to regret the treatment he bestowed on the truest friends he ever had, after he treated them poorly when his own circumstances changed. While acting the gentleman, Pip humiliates his true friends and is ashamed of their place in his life...... none-the-less...... Pip, Magwitch, and Biddy are the most loyal and genuine people he will ever know.

Another example would be Pip's relationship with Pumblechook..... the man who looked down on Pip and begrudged him the bread he served him for breakfast. When Pip's "expectations" arrive, Pumblechook is only too happy to seek out his company, only to once again avoid and look down on the boy when his fortune reverses.