Why does nobody teach respect anymore?

I went to pick up my nephew from school and saw kids back talking to teachers, not shaking hands, slouching around like they own the place. When did we stop teaching kids to look adults in the eye and say yes sir and no ma'am? My kids do it and people notice. They get treated better because they show respect. It's not hard, it's just discipline. This whole generation needs someone to give them a reality check.