I've got an article here that purports that secondary schools are an anathema to a child's creativity. It isn't the school's intention to do that, of course. We do want our kids to grow into thinking, creative adults, but our processes often send the wrong message.
I think there is a difference between (1) encouraging imagination and (2) nurturing creativity. Schools tend to focus on the latter at the expense of the former, which is what turns off most kids.
Imagination refers to wild flights of fancy, ideas that suggest "anything goes". These ideas are the most fun to play with, sometimes the most dangerous and scary too, but that's why imagination is so much fun, so outside of our mundane reality and existence. But when schools tell us to focus on the real and not on the imaginery, when they tell us to be practical, suddenly life becomes boring and our motivational engines sputter and die. All we want to do is sleep because we can't be our naturally wild and crazy selves any more.
But that's just imagination being curbed, which is not quite the same thing as creativity, though perhaps only one of creativity's more special ingredients. We define 'creativity' as 'out-of-the-box' thinking, but in order to achieve that level of intelligence, we need to know what's INSIDE the box first. That's what schools specialize in, putting students inside a package of social norms, rules, customs, expectations; wrapped in a common knowledge of science, math, languages, and occasionally humanities so that at whichever level we leave school at, we leave with a cohort of peers who know exactly what we know and so we all start out making lives for ourselves from the same, equal starting line. That's fair.
The assumption is that as long as we stay in the box, everything's nice, everything's safe and everything's fair. It's only a rare few who realise that it actually isn't, and they are the ones who start thinking 'outside-the-box', yes, the real creative ones.
Creativity (a.k.a. 'innovation') starts with dissatisfaction, and it seems that at JC level, only GP (and maybe elements of the Arts and Humanities) teaches that the world isn't perfect, that the world doesn't follow the rules that are supposed to work to keep society nice for everyone, that the world isn't fair in the way that math and the sciences with all their rules and formulae tell us it is. Just-follow-the-formula-and-everything-will-be-correct is nonsense in reality, but that's what's inside the box. It's a seductive message to be deluded by and take comfort in, but it's only the dissatisfied and unhappy who question the formulae and eventually become the creative ones.
Imagination, as I mentioned before, is a wild thing. Creativity is our ability to harness our imagination, tame it and make it go where we want it to go. We are creative when we can discipline our imagination, making it work for us. There's a riddle that goes, "what do you need to know before you can train a dog?" to which the answer is, "more than the dog!" That's where most of us are today, in the process of learning more than the dog, those of us who are looking to be creative in spite of our school experience.