Dr. Laura:
All teenagers will start asserting "their" values as part of asserting their independence.
The real question for parents is "what values do your teenagers have?"
If you placed them in "child care" from 2 to 5 and then in "public education" from 5 until now, don’t be surprised when their values differ from your own. Your values were clearly taught -- you taught them to look elsewhere for values and they found them.
Why are you surprised when, after neglecting them for all these years, their peers have more influence over them than you do?
Your teenagers are not "sassing" back. They are simply expressing their values -- the values that you never taught them and they learned on their own.
By the way, I did not have rebellious teenagers. Somehow, my stay-at-home wife had time to teach them our core values. I'm not saying my children turned out perfect because of perfect parenting. I am saying that practically perfect children adopt the core values of involved and caring parents.
Gary