Final answer:
Risa likes her job at the Graveyard because it is most interesting, indicating that the work is engaging and intellectually stimulating. The parallel narrative of Isabel, who becomes more cheerful after changing her work environment, supports the notion that fulfilling work can have a significant positive impact on one's mood and mental health.
Step-by-step explanation:
The question "Why does Risa like her job at the Graveyard" appears to refer to a character's personal experience with their job, which suggests a context likely found within a work of literature or a narrative text.
From the information provided, Risa finds the work at the Graveyard most interesting, which implies that the job is engaging and possibly provides variety or a degree of intellectual stimulation.
Additionally, there's mention of Isabel, who seems to be working at a Canadian Recreation Hut in Boulogne and experiences a positive change, moving from being very depressed to appearing more cheerful in her letters.
This change in Isabel might hint at the fulfilling nature of the work they're involved in, which could similarly be the reason Risa enjoys her job at the Graveyard. It may provide her with a sense of purpose or a much-needed change from a previous state of mind.