Ngl. I’ve hit my nipples on things and it sucks. My dogs have ran their nails across them and they burn for the rest of the day. I totally feel that pain
However I’m a guy and have had to apologize multiple times to women because my eyes just trail down to the chest. I don’t know psychosomatics of it, but it’s not something I consciously intend to do.
Beyond that, I don’t mind whether women do or don’t wear a bra. Breastfeed in public if needed. It all should truly be none of my business. However, I donate to breast cancer research every year for a reason. And that reason is I think about boobs. My wife has my favorite pair though.
Anyway, I digress, I never really knew the original purpose of them and figured I could satiate my curiosity and have a conversation about boobs with people