Final answer:
The action of Mr. Steward returning the button unit to the Lewis home after his phone conversation with Norma creates a sense of unease and suspicion among the Lewises.
Step-by-step explanation:
In the story, the action of Mr. Steward returning the button unit to the Lewis home after his phone conversation with Norma affects the Lewises by creating a sense of unease and suspicion. The return of the button unit suggests that Mr. Steward has been listening in on their conversations and invading their privacy. This revelation undermines the trust and sense of security the Lewises had in their own home. They now feel violated and unsure of who they can trust.