Final answer:
The narrator's main issue with Bartleby is his refusal to perform the tasks asked of him, which escalates to him ceasing all work entirely.
Step-by-step explanation:
The narrator's main problem with Bartleby is that Bartleby refused to perform tasks he was asked to do. Initially, Bartleby was a diligent worker, copying documents with great zeal. Over time, however, he begins to decline the tasks requested by his employer with his characteristic response, "I would prefer not to."
This passive resistance grows until Bartleby ceases to do any work at all, instead choosing to remain in a state of revery. Despite the narrator's attempts to reason with him, offer alternative employment, or even dismiss him with a generous severance, Bartleby steadfastly refuses to alter his behavior or explain himself, leaving the narrator feeling perplexed and frustrated.