Manners

Is it exhibiting good manners to tell someone that they have something in their teeth/nose/hair?
Also, to tell someone that they have toilet-paper attached to their sneaker after using the restroom?
Does it exhibit good manners to say to someone when their voice has elevated to the point that other people are looking in your general direction, that they are being too loud on a personal subject and you are in public...?

I often wonder where people were raised. Be it a barn, the back woods, the circus... I guess I am a manners snob, because all of these things bother me tremendously and I would expect someone to do the same for me if I were displaying something in my teeth, something hanging out of my nose,(which has never been the case for me, as this is something I've always made sure of never happening to me...)or the toilet-paper thing... as this would just seriously be immensely embarassing... Do you wonder about the people that HAVE that thing in the nose, that just don't care that it's there?
Help a girl with manners understand.