Pip does not want Joe to visit Miss Havisham, because he is embarrassed.  However, Joe is a kind and sincere man who just wants what’s best for Pip.

Joe dresses up in his Sunday best to go with Pip to see Miss Havisham, the wealthy but reclusive woman he has been visiting.  Joe is trying to look nice, but Pip feels that “he looked far better in his working dress” because he is so uncomfortable dressed up “like some extraordinary bird” (ch 13, enotes etext p. 70). 

Joe is so uncomfortable that he talks to Pip instead of answering Estella or Miss Havisham.  He refers to Pip as a friend, and is unwilling to address the area of indenturing Pip as an apprentice.

Miss Havisham glanced at him as if she understood what he really was, better than I had thought possible, seeing what he was there.... (p. 71)

She declares that Pip has earned “five-and-twenty guineas” and has him give it to Joe to take him on as an apprentice.  Still addressing Pip, Joe thanks him for his generosity.

Joe cares about Pip like a son.  He has seen what the boy has been through, and always treated him well.  His wife lords over both of them, and terrorizes Pip.  He expected Pip to be his apprentice, but he never expected to get anything for it.  He feels uncomfortable in the presence of a wealthy woman like Miss Havisham.

Joe is one of the few genuinely kind people in Pip's life, and one of the only ones with no agenda.  He cares about Pip, and loves him, and wants what's best for him.