The hardest job kids face today is learning good manners without seeing any - Fred Astaire. This is more true than ever these days. Disrespect towards ALL elders is the number one sign of bad manners no matter what your age is.
Never confuse etiquette and manners. Bad etiquette is using your dinner fork on your salad. Bad manners is pointing out that someone used their dinner fork on their salad. Manners will always trump etiquette.