Missing manners

Where have good manners gone to now-a-days?

I was brought up that if people were talking and you wanted to speak to one of them you waited until they had finished their conversation. You didn`t go up to them and butt in. Neither do you walk through the middle of two or a group of people talking, you walk round them, or behind them. And, it`s not just the young people who do this. I was talking to someone yesterday morning, and starting to say about something that`s worrying me when someone barges through the middle of us, thus ending what I`d just had the opening and opportunity to say and to ask.
It was so frustrating and annoying.