In act one of Arthur Miller's The Crucible, John Proctor talks with several people before he speaks with Giles Corey, so we get a feel for how Proctor speaks to others. He is a practical man who does not believe the girls' play-acting (because Abigail told him the truth) and has no patience for Parris or for Putnam. While he does not hide his disdain for these two men, he is respectful of Rebecca Nurse. This all makes Proctor a fairly good judge of character from the very beginning, despite his incredible misstep in having an affair with Abigail.

When Giles Proctor enters the room, everyone knows it. He is a cantankerous octogenarian who speaks his mind and does not care about the consequences. He does not like the Reverend Parris and does not like Parris's continual whining about money--and he is not afraid to say that to the man's face. It is a rather bold position in this time and place, for religion and law were nearly the same.

What we discover about Giles is that he is overly fond of suing people; he has brought suits six times just in the past year, as a matter of fact. Giles takes this aspect of his life quite seriously, but Proctor clearly likes the old man and teases him a bit about it. 

Proctor, familiarly, with warmth, although he knows he is approaching the edge
of Giles’ tolerance with this: Is it the Devil’s fault that a man cannot say you
good morning without you clap him for defamation? You’re old, Giles, and
you’re not hearin’ so well as you did.

Giles. he cannot be crossed: John Proctor, I have only last month collected

four pound damages for you publicly sayin’ I burned the roof off your house....

Despite the fact that Giles brought one of his ridiculous suits against Proctor, the younger man is still respectful and even likes Giles. Proctor understands that Giles is old and does not hear as well as he used to, something which creates needless ventures into court but which is essentially harmless.

The most important thing we learn about these two men in act one is that they are united in their dislike of Parris and Putnam, two villains in this story. Both men hope Reverend Hale will restore some sanity to this situation and this town, and they have a dry sense of humor, as well (note their desire to be part of the "party" which is trying to oust Parris). As they are leaving, Giles makes a semi-serious threat against Putnam, as well, and Proctor is right with him. 

The relationship between John Proctor and Giles Corey is one of the most delightful in this play, and it is evident from the first time we see them together in act one.