Someone whose job is to wait on others all day becomes an expert reader of their moods and faces. He can spot the quiet bitterness of a customer who sees that new clothes can only do so much, and the silent triumph of one who looks good in them. The served, meanwhile, barely register that he is there.
Where ordinary customers bargain and question, the wealthy buy with few questions and no haggling. Price simply stops being part of the conversation. A shop worker sent into such a home sees a different world in how little money seems to matter.
Seeing a richer world up close can break a poor worker out of a routine he had accepted and fill him with an urgent sense that he too could rise. Trying to act on that hope can cost more than he can afford, and can overturn his life rather than improve it.
A quiet, respectable town can depend on harshness that its comfortable members never have to look at. When a poor person tries to rise, he ends up face to face with the cruelties his own existence depends on, and losing that innocence can push a timid person into his first act of rebellion.
A poor person who openly blames the powerful for her ruin is dealt with quickly and harshly. Others hear about it only secondhand, which is how such punishments usually stay invisible to everyone but the people around her.