She feels insulted when Effie makes a comment about her district, because most kids in her district have never had enough to eat, and so when they saw fine food the last thing they were thinking about was table manners. (When they were eating together on the train, Effie told Katniss and Peeta that she was glad that they had some manners. She told them that the tributes from the previous year had eaten all of their food with their hands, like a couple of savages. She was glad that Peeta and Katniss had managed to come over the "barbarism" of their district.
Well, using common sense here she will probably be a little mad about how they describe her home.
Cinnas advice is practical, yet more risky that Haymitch and effies simple 'stay alive'