Pip has a run in with the convict for the first time. This is the event that leads to Pip's paranoia through out the early part of the book.
The Christmas dinner where 2 important characters are introduced to the story. It also adds to Pip's paranoia with the tar scene. It gives us a good idea about how Wopsle and Bumblechook feel about Pip and what kind of person he is especially when he changes his mind for greed.
The vital scene where Estella calls Pip common and changes his life forever. He becomes determined to raise his status. This can be seen as the jumping point of the plot from the build up.
Pip is bound as Joe's apprentice and joins him in the forge. This action makes Pip view his life as even more common and he grows ashamed. This also helps push Pip to become more of a gentleman along with trying to change Joe.
Pip and Joe return to the house to find Mrs.Joe unconscious on the kitchen floor. This sparks a mystery and makes Mrs.Joe unable to perform most tasks. This is a big shock and changes Mrs.Joe greatly. It is a huge character development!
A strange man pulls Joe and Pip aside at the tavern to tell them Pip is to be made into a gentlemen and has come into a large inheritance from a secret accomplice. This new has made Pip's dreams come true and creates a turning point in the story where Pip begins his new life and is treated differently this is where the story shows that Pip's great expectations are finally coming true.