She tried to imagine what it would be like to have worked fifteen years in Frankenberg's department store, and found she was unable to. (1.3)
When Therese meets Mrs. Robichek, she sees a potential fate for herself: working (and probably dying) at Frankenberg's. Those are the choices society gives to young women in this time period—work a dull job until you're married, or don't marry and stay there forever. Yikes.
"At least you're not going to make the same mistake I did, to marry because it was the thing to do when you were about twenty, among the people I knew." (7.76)
Carol probably got married in the 1940s, when it was even more expected for women to marry. Therese is living at the beginning of a new society that's starting to be more accepting of single women. But it's just starting; there's still a long way to go.
"Hear of it? You mean people like that? Of course." (8.71)
Richard is talking about gay and lesbian people. His reaction in the 1950s sounds like people today might talk about yetis or bigfoot. Heard of them? Sure, but we've never seen them in the wild.
Therese glanced at him. Richard's aversion to the wealthy, to the bourgeois, was automatic. (9.100)
We get a few small tastes of class differences here and there. Richard's family isn't in poverty at all, so we're not sure what his "aversion" is, and it isn't explored. But there is a significant class difference between Carol and Therese that occasionally causes tension, like when Carol offers to pay for things.
"They're not horrid. One's just supposed to conform." (11.74)
Carol, who grew up in the 1930s, doesn't rebel against conformity the way Therese does. Perhaps this is the "courage" Carol sees in Therese and begins to draw from as the novel progresses and Carol rebels herself.
"You're in some kind of trance! It's worse—" (13.19)
Richard believes in weird lesbian magic, it seems. Although he has heard of lesbians in society, he doesn't believe they're a normal part of society, and he clearly thinks Therese has been tricked if she's now a part of the lesbian crew.
"I'll tell you one thing, I think your friend knows what she's doing. I think she's committing a crime against you." (13.29)
It's difficult to tell if Richard says this because Carol is older, because she's a woman, or both. But the same-sex relationship is not acceptable in society. Richard would probably have a different reaction if Carol were a man.
"And you have to live in the world." (16.89)
Once again, we see Carol's conformity. She makes a point, in that she has to live in the world as a wife and as a mother. But once she loses those two roles at the end, she can live in society however she sees fit.
"In the eyes of the world it's an abomination." (16.85)
This is probably the strongest word speaking out against same-sex people in the book. How have attitudes changed since 1950, and in what ways are they the same? Which parts of society still believe that same-sex relationships are an "abomination"?
She thought of people she had seen holding hands in movies, and why shouldn't she and Carol? (16.19)
Again we see a hint of Therese's disregard for societal norms. She wants to hold hands with Carol in public, but Carol won't let her. Therese also doesn't really try, so she only thinks about rebelling but doesn't actually do it.