In A Raisin in the Sun, the Younger family live in a very cramped apartment on the South Side of Chicago. When one sees just how cramped it is, one can immediately understand why Mama Younger is so keen for her family to move out to the suburbs, where everyone will have so much more space and privacy.
For now, though, the Youngers have to make do with their cramped accommodation as best they can. This involves sharing a bathroom in the hall each morning. In fact, not only do they have to share that bathroom with each other, they have to share it with their neighbors as well. In other words, it's a communal bathroom, a sure sign of the relative poverty experienced by the people who live in this apartment block.
Under the circumstances, it's not surprising that none of the characters seem particularly happy when we first meet them. It would seem that the cramped living conditions in which they are forced to live—not to mention the communal bathroom they have to share—are really getting everyone down.
That being the case, it's essential, for the sake of everyone's well-being, that the Youngers move to a new place in the suburbs as soon as possible. With the insurance check she's received from her husband's death, Mama Younger should now be in a position to make that happen.