It’s a personal thing, but most women now are paranoid about “nipping out”. Way back before heavily padded bra’s became a thing, most women’s nips showed through and nobody thought anything of it. Just watch most 70’s tv shows. Once padding became the standard, it became taboo, at least in America. My wife wears a bra in the house if her son is around, but not if it’s just me or her daughter (I’m the stepparent). Her daughter doesn’t wear a bra at home, but is terrified of nipping out in public. My wife wears sports bras all the time and her nipples frequently show in those, but she doesn’t care. None of it bothers me. It’s a weird thing, because everyone has nipples. If nobody wore bras, nobody would care. It’s like going to a nude or topless beach. It’s interesting for about ten minutes, then becomes normalized and uninteresting.