Oh I had a bit of grumble at the shopping centre today about this. Younger generations seem to be getting more selfish, which lack of basic manners can stem from. Inconsiderate is the word. It's a cross cultural thing too. A lot of 20 something year olds will admit this themselves. There could be a variety of reasons for this but I am familiar with one personally. Back in the 80's when I was raising my kids, there was this huge push to reason with children rather than using authoritative discipline. What a crock. They're children. They don't have the reasoning abilities of an adult. I was brought up with "children should be seen and not heard" parents and beatings that were acceptable in Victorian times, and yes, that had to change, but it went too far the other way and created what we call "The Me Generation". Supernanny was great, she had some great ideas and she could teach them well because she went home to a house with no kids. This is how it happened. "Professionals" with degrees in child psychology and no kids, pontificating. I'm not bagging Supernanny and some of her techniques, I saw her get authoritative at times too. This experiment into a new way of parenting failed, because it wasn't comprehensive.
I think this mixed with violent video games which have been shown to lessen a child's ability to feel empathy have had a huge negative impact on social cohesion. And while the rights of the child are monumentally important, and so is teaching them their rights, they haven't been taught that with rights come enormous responsibilities.
Social change takes a long time and there are always unforeseen problems when renovating. As long as we can admit when we screwed up and learn from it we should get there in the end. Doesn't mean I'm prepared to take crap from whippersnappers though.