Hunger games chapter 12-16 katniss moves from playing defense (hiding) to now playing offense (attacking) the careers. what happens to make her do this, and why is this important?

What is implied in this sentence from mark twain's "the ? 1,000,000 bank-note"? i was puzzled, and wanted to discuss the matter a little further, but they didn't; so i took my leave, feeling hurt and insulted to be made the butt of what was apparently some kind of a practical joke, and yet obliged to put up with it, not being in circumstances to resent affronts from rich and strong folk.