I hate to break this to you....but a lot of us would have said the same thing to our parents if directly asked....at age 18. In my family....*I* was that kid....the peace keeper, wanted everyone to be happy. I would have most definitely said the same thing. I also thought *the world* of my maternal grandparents...but as I aged I looked back on some of their habits as a bit troubling at times, especially with respect to how they raised their younger children (my mother is much older than her siblings). As you get older and look back on your life...you see things more clearly than you did as a child in a fairly sheltered environment. And an 18 year old, no matter how mature they can seem (and some can seem like they're 30 year olds)... still is a child, one that is still developing and dependent on his parents for care.
Again...I love/loved my parents...my father has passed, but there are techniques that they used as younger parents in the late 60s and 70s....that their educated daughters did not replicate when they had children 30+ years later. That doesn't mean we're not all a family...but simply that there is almost always room for improvement as generations progress through time.