This is from Peter Gray's Psychology Today blog this week:
"We come into the world as little scientists, pre-programmed to try to understand everything around us. Nobody has to tell us to explore and learn about our environment; we do it naturally, all our lives, in increasingly sophisticated ways, unless someone turns it into work by trying to make us do it."
So true! There is no better way of taking the joy out of learning something than telling me there will be a test on it later ;-)