Ambiguity

Exactly why does Bartleby always "prefer not to"? Why can't he make friends, or communicate? What's at the heart of his rebellion? Why doesn't he quit and get a different job?
Why does the Boss have sympathy for Bartleby?
What else in the story seems open to individual readers' interpretation?

Bartleby always prefers not to because in his past job he would have no one to hear from, all he would do would be destroy the mail that was never received. Therefore he would not communicate and his past job "sucked" his emotions out due to all the things that people would not receive. Bartleby's previous job had completely isolated himself from the community and society converting him into a monotonic person who did not wish to do anything but to be alone in a stable place. One reason why Bartleby does not quit and get a different job is because he does not seek to have a new job and he states there is too much confinement. “There is too much confinement about that. No, I would not like a clerkship; but I am not particular.” I believe the lawyer has sympathy over Bartleby because does not have sufficient information about Bartleby to judge him and also because he wanted to find the source of why Bartleby would act this way. What jumps to me and is open to individuals interpretation is that if he would not communicate or not make friends how did he manage to get a girl in his office? As well how did he communicate to her surely he did not tell her I prefer not to because he asked the lawyer to come back to his office later.