He walked briskly down the street. He was trying to do everything briskly these days. Briskness, he had decided, was the one common characteristic of all successful businessmen. The big shots up at Head Office were absolutely fantastically brisk all the time. They were amazing.

This quote comes at the beginning of the story and highlights Billy’s youth and inexperience. Billy is only seventeen years old and an upstart in the professional world. Thus, he looks up to other successful businessmen and immaturely seeks to mimic their behavior. His naïve admiration for their briskness, rather than actual business acumen, is purely superficial and exposes Billy as a young man who is in over his head.

She seemed terribly nice. She looked exactly like the mother of one’s best schoolfriend welcoming one into the house to stay for the Christmas holidays. Billy took off his hat, and stepped over the threshold.
 

This quote comes when Billy first meets the landlady, and it further underscores the way Billy’s youthful inexperience leads him right into her trap. It is significant that Billy compares the landlady to a best friend’s mother. As a young man in a strange place, Billy craves the safety of a family home and the love and protection of a mother. The threshold Billy steps over is a literal one, but it also represents the point of no return for naïve Billy Weaver.