A lot of parents think they should decide what's best, and then make their child do it. If he turns out 90% the way they wanted, then that's a pretty good success.
But consider what happens if I make my kid 90% of what I think is good. Then he takes his values, and makes his kid 90% of that. And then the next kid is 90% as good as his parents. And so on. See how it gets worse every generation? As a percentage of the original, the generations go 90%, 81%, 73%, 66%, 59%, etc
TCS aims for children to be even better than their parents. For that to happen, they are going to need to be something more than not quite perfect copies of their parents. You can't just take the parent, copy it with only a couple flaws, and call it better. That's obviously going to be a little worse.
Children, to turn out better than their parents, are going to have to disagree with their parents about at least one thing, and be right. Parents need to allow and encourage that, not suppress it.
A lot of parents are pretty sure they know what’s best, but they also know that they themselves haven’t achieved that best. Like, they never finished college, but they think they should have, and they think their kid should. A parent might be happy with their kid achieving 90% of the parent’s values, which might be a greater percentage than the parent has achieved.
The parent has in mind improvement through the generations, but improvement measured against a mostly unchanging set of values. The parent does not have in mind that they should expect and encourage their children to improve on their values in addition to improving on attaining those values.