I agree with Jock's statement about slovenliness and bad manners . . .and go a bit further. Slovenliness is bad manners in any context, public or private. It disrespects any context into which it is introduced and disrespects all others upon whom it is thrust. I also believe this extends from manner of attire to manner of speech.

Public attire and public speech has become less a personal expression than a public statement of how little some care about the feelings of others. You can see and hear it at weddings, funerals, graduations and the list goes on.

Good manners is simply respect for those with whom we associate at work, in the neighborhood, and various occasions with differing levels of formality. There is no excuse to leave them behind when venturing out into the public square.