Would you want some one to tell you if you had something that didn't belong on your face? In your teeth? In your hair? I think I would. It might be a little embarrassing right at first, but then at least you know you aren't walking around all day looking stupid.
But what if you stink? Would you want someone to tell you that? And how do you tell someone that? Obviously it has to be something other than "Hey buddy, you smell." Especially if it is a friend or family member.
At my work I come across more smelly people in a day, than most people do in a month. Lucky me. Now, the problem I am having is, is it OK for me to tell them that their breath smells so bad it is making me gag? That their clothes smell so much like old cigarette smoke, the smell will linger long after they are gone? That showering once a week should be common practice for those over 10? Something tells me no. If I said, "excuse me, but can I have you not breathe in my face, your breath smells like something died last week has yet to be found." I would be reported to my manager for bad customer service. She would probably be on my side, but that would not matter in the long run.
Is there anything I can do to stop the stench?