If you staying with your in-laws, how do define improper attire? Does not wearing a bra considered as improper?

I used to stay with my in laws for 1.5 years and was used to going braless at home. So when I moved in, I would wear baggy shirts and hunch a little forward when walking past my father in law. In front of other women, I wouldnt bother. I didn't think my father in law noticed but once in front of family members he commented 'hey you dont wear a bra at home right!' and everyone laughed. I was a little mortified but well i would wear a baggy shirt and hunch forward all over again rather than wear a bra 24/7. Nothing beats having your own home and wearing whatever you want though!