We have more than one generation of kids that have no respect or manners for anyone. Is it their fault?  No!  It's the parents fault. Today we have parents that are mostly kids themselves, and have no idea how to raise kids, and they are too lazy to correct them when they need it. Probably because they were not corrected when they were raised either. They were raised mostly by TV. It's a cycle that keeps repeating itself and will............. 
I'm in a position where children are in my home many times. I have no problem correcting them. A child that comes into my home and "trashes" my house will get a reprimand from me if their parents do not take control. If your children hear you cus out the store clerk, strangers who pull out in front of you, someone who doesn't give you the best service, don't be surprised if they mirror you. Fathers and mothers who don't respect each other and fight and cus each other out, don't be surprised if your children learn the same.
When spanking and real discipline went out the window, so did respect and manners. Children need boundaries and actually want them. A child left to themselves is trouble waiting to happen. Many people worry about our economy and how everything is eroding. However, we are raising children who think that they are owed a living without work. No values, virtues, or ethics have been instilled into them, and then we wonder why the kids have turned out so bad.
I was strict with my son. I told him if he always told me the truth, and was sorry for what he had done, there was no punishment. However, if I caught him in a lie about anything he did, the punishment was severe. He was taught respect for those older, and especially respect for women. If he had a smart mouth, there was consequences. I spanked him when Dr. Spoc was telling everyone not to. He has grown to be a fine father and husband, respected in his career, and liked by everyone. He raises his sons the same way. I'm proud of him.
You don't have to be the perfect parents, but some things must be instilled into children to help them in their future life. If not, then we all suffer with future generations with no respect, values, or manners.