A second scene would be when Magwitch has his flashback. It's a flash back that Magwitch is having. His hard childhood struggle for food then meeting Compeyson. This flashback shows a lot of who Magwitch is and that he is not as bad of a person as he come off as. He only steals for food and he doesn't try to be someone he's not. Magwitch is an important character because he is the person who has been looking out for Pip and giving him money. He couldn't have become a gentleman without him.
The third scene is Earlier on in the book when Pip is meeting Miss Havisham for the first time. She is one of the people in Pip's life who he has looked up to and no matter where Pip goes something about her always comes up, especially since he thought she was the one providing him with money.