There is much suffering in Sula, which has much to say about the relationships between men and women, issues of race and gender, and the ways suffering might actually sustain a character. The women characters suffer because of the men in their lives; men suffer from not being able to provide for their families; both suffer from the restrictive gender roles that dictate their lives; and many characters suffer simply because of the color their skin. But in some ways, suffering is also what keeps characters going and gives them a sense of purpose.
Suffering is like a drug for some characters. Without it, they wouldn't know how to live their lives.
The residents of the Bottom don't suffer because of anything they've done. They are the victims of racism, gender discrimination, and poverty, and there's no way for them to escape these.