Rudeness - nature or nurture?

I was "people watching" at the mall the other day when I noticed a mother say "shut up" to her son. My first reaction was to think what could be so bad that would warrant her to say that. Then I realized that perhaps her own mother or father probably talked to her in that same manner. It really disgusts me because when you look at the whole thing, there are just some people who don't deserve to have children when there are so many misguided kids in this world. When parents are too busy with their social life, too involved in their career, or too busy shopping at the mall, that taking care of their kids becomes somewhat of a burden. Kids only emulate what they see in this world. It is no wonder that kids these days are so rude and impolite - blame it on their parents! If you want to have good kids, it's starts by people looking at themselves and changing for the better.