How does Katniss show that she is stubborn?

There are many parts in the story where Katniss shows she is stubborn. During training, she aims her arrow at the table of the Gamemaker skewering an apple in the mouth of a roasted pig that is on the table. She then walks out without being dismissed. She also refuses to give into President Snow when she changes the rules of the game by threatening to eat the poisonous berries at the end of the game.