Upon returning home, Pip is barraged with questions about Miss Havisham by Mrs. Joe and Uncle Pumblechook, who has ridden over for tea. Yet, because he himself has such a fear of being misunderstood, he feels fearful of Miss Havisham being misunderstood as well and refuses to answer any questions about her, even as Mrs. Joe and Uncle Pumblechook bully him for information. Finally, he begins to answer their questions with sensational lies, which Mrs. Joe and Uncle Pumblechook believe. They marvel at Pip's account in awe and relate them to Joe, who is equally accepting and amazed. Pip starts to feel guilty for deceiving Joe (though not for deceiving his aunt or Uncle Pumblechook). Mrs. Joe and Uncle Pumblechook giddily speculate on what Miss Havisham might do for Pip.
Note the difference between this dishonesty and that of not coming clean to Joe about the pantry theft. Here, Pip lies out of compassion, to protect someone's dignity rather than to preserve his own false reputation. The fact that Mrs. Joe and Uncle Pumblechook believe Pip's lies show how little exposure to upper class they have—they believe it really could be as alien and sensational as Pip's description.
Later, Pip confesses privately to Joe that the story was a lie. Joe is aghast and asks Pip what possessed him. Pip tells Joe the truth about the day, including Estella's insults and his shame at being "common." Joe replies that lies are lies, no matter the motivation for them, and that "if you can't get to be oncommon through going straight, you'll never get to do it through going crooked." He then reminds Pip that Pip is already uncommon in stature and in letters. When Pip remains discouraged, Joe reminds Pip that everyone must be common before they can develop uncommon skills. He resolves not to reveal the truth to Mrs. Joe for fear of upsetting her, promises Pip he isn't angry at him, and advises Pip to pray for his lies. Yet when Pip gets in bed, all he can think about is how common Estella would find Joe, Mrs. Joe, and his home. The adult Pip narrator notes that this day was the first link in a long chain that determined his life's later course.
Joe takes the term "uncommon" to mean "extraordinary" or "unusual," rather than "upper class." This misunderstanding is evidence of Joe's own priorities—he isn't focused on differences in class and social status. Instead, Joe concentrates on individual self-worth, emphasizing hard work and personal morality. Still, it is difficult for Pip to share Joe's value system, preoccupied as he has become by Estella's opinions. This day is formative because it has instilled Pip with the ambition to be "uncommon" and has taught Pip to judge himself according to Estella's superficial standards —Pip will live by these new principles for a long time.