I fully understand. I have many a retired/active teacher in my family, and I myself work with kids who are "in the system".
The parents I deal with day in and day out are....to say the least, frustrating. It seems 90% have a goal in life that is solely to keep their child from understanding action=consequence, whether good or bad.
I have to constantly remind myself that the people I deal with daily are not the norm, that addicted parents, jailed/prisoned parents, etc, are not what goes on in "normal" society.
We do the jobs that we do so that 1 out of a million people we deal with....we might just make a difference (ok I exaggerate, but that's how it can feel).
Just remember that you do what you can, you try to provide the services/structure/support/caring that you believe the child needs, and hope that one day it will be received with gratitude. Don't get down, sometimes those kids/parents don't respond now, but they will remember. One day what you have said/offered might click.
I've had kids come back/call years later and say, "I remember what you said/did and it didn't do anything, but I know now that you were right/helpful/caring, and that means something to me now."
KH is a great place to vent, and all can empathize, and many can relate!!!
You are not alone in you frustration.