Ever tried to train a cat? I'm talking the kind of training it takes to get them to do tricks – not potty training or not-scratching-the-furniture training. I can't say as I have ever tried. It must be nearly impossible, but it must be doable. However, knowing cats, I do think you would have break the poor thing's spirit a little and stifle a good chunk of its independence to get it to do what you want, the way you want, when you want.
I reckon teaching kids (of any age) is fraught with the same potential pitfalls. But it does get a little easier as they grow older because they've so often had their wilder spirits squashed before they reach you. The good thing, though, is – unlike trained cats – human children do not need to spend the rest of their lives cowering skittishly, they can have their spirits lifted and their independence reinvigorated.