I was waiting at the supermarket checkout yesterday and just looking around as you do, when I noticed a young woman at the next checkout packing her shopping. She was dressed casually, like me, but she had this thin vest top on. As someone earlier said, your gaze has to fall somewhere and it was obvious she was not wearing a bra. Nothing wrong with that, but she did have the 'chapel hat pegs' look about her. For all I know she may have been thinking 'I wish I'd have put my bra on'! Maybe she'd just been in the cold aisle! BTW I used to go braless when younger and still do in my garden, but mine never stood out like that!
Men in shorts, socks with sandals whatever don't bother me. Don't think I'd like to get an eyeful when someone bends down showing half their bum though!