How we cite our quotes: (Chapter.Paragraph)
Quote #4
Now Carrie was affected by music. Her nervous composition responded to certain strains, much as certain strings of a harp vibrate when a corresponding key of a piano is struck […]. They awoke longings for those things which she did not have. (11.16)
Just listening to music stimulates Carrie's ambition to acquire more stuff. This is also true of her trips to the theater later in the novel, and makes us wonder what role culture has to play in stirring up people's ambitions to be materially successful.
Quote #5
[…] she could not help thinking what a delight this would be if it would endure; how perfect a state, if she could do well now, and then some time get a place as a real actress. The thought had taken a mighty hold upon her. It hummed in her ears as the melody of an old song. (18.15)
Imagining the prospect of how perfect her life will be in some future moment when her ambitions are realized is a frequent pastime of Carrie's. And it's epitomized perfectly by the comparison here to the melody of an old song stuck in one's head.
Quote #6
The result of this was that she secretly resolved to try. It didn't matter about him. She was not going to be dragged into poverty and something worse to suit him. She could act. She could get something and then work up. What would he say then? (37.36)
Sometimes haters can be great motivators (sorry for the corny rhyme). But when people do things to prove others wrong, ambition can become a bitter-filled enterprise.