When I was quite young, my Irish Grandad sometimes allowed me to walk with him around town (a couple of blocks from one end to the other)"to town" ie the post office or dominoe parlor, the cafe/bait shop, the "crik" for fishin' & such. Whenever Grandad met up with ANYONE, they were always Mr., Mrs., or Miss so & so--man, woman or child. Quite simply, this was considered common courtesy. Common courtesy, as with common sense is uncommonly found in these times. To this day, I feel quite uncomfortable referring to strangers or older folks by their first names.