Final answer:
The narrator's feelings about her family's behavior during dinner are best illustrated by descriptions of dinner as an 'agony' and expressing feelings of isolation and unease through different characters' negative experiences during meals.
Step-by-step explanation:
The piece of evidence that best reveals the narrator's feelings about her family's behavior during dinner comes from the excerpt where the emotions felt during the meal are vividly described. The narrator mentions, dinner was an agony, indicating a distressful experience rather than a pleasant family gathering.
Furthermore, the use of phrases such as burned her finger and much hair, and the aunt being worried and grieved, along with the uncle's hurt and faintly hostile tone, all serve to underscore the tension and discomfort during the meal.
Another excerpt talks about feeling isolated and disconnected while observing unfamiliar customs at a dinner, which indicates the narrator's struggle in adapting to a different family's dinner habits. Lastly, the moodiness and petulance displayed by a character during dinner which gave someone else a feeling of uneasiness also gives insight into the negative emotions associated with the mealtime.