How have expectations played a big role until Chapter 19?

In Chapter 19, Pip is readying himself to leave for London as his benefactor has requested. Prior to this, Pip's expectations had often changed. Earlier, he believes Ms. Havisham has a plan for him. He believes she requires his presence, and that she's taken in interest in his future. Unfortunately, she hasn't taken the interest he expected. Rather than introducing him to society, ahe pays for his indenture. Pip is devastated..... he could taste the opportunity of becoming a gentleman, and suddenly it was snatched from his grasp.