Politeness As We Know It.

I remember when I was just a little bit younger probably even as young as 3 or 4 how my family would teach me how to be polite. I would say yes mama or yes sir, or no mama or no sir or thank you or even no thank you thats how I was brough up. I had to be polite. So why is now everywhere you go people seem to be getting more and more disrespectful? People don't seem to say things like that anymore. I really never here people say things like " No thank you" or even a simple "Thank You" I would even take a "Have a nice day" I don't even hear that anymore. So what happend that made people stop acting so polite? I miss those days .