Manners

I`m going to have a little (or perhaps a big!) grumble today!

Where have peoples manners gone to? And I don`t just mean from young people.

I was always taught that if you want to speak or talk to someone and you see that they are already talking to someone else, you wait (and if possible at a reasonable distance, so that you don`t stand to purposely hear what they`re talking about) until they`ve finished talking to that person.
Am I the only one that`s been taught that?

I constantly find at work and in other places, in the street, anywhere, that people have no such thought, they just barge in and start their own conversation with the other person, regardless of the conversation already going on between two people. AGGGHHH........ it makes me so mad!