How to deal with a fertile imagination?

Sometimes I see myself tripping out so badly that I wonder how long have i worked on decreasing the negative effects of my imagination. And sometimes I also think if i've never had done so much psychoanalysis, what would I have had become? Imagination is something marvelous, I don't doubt, but it's easily possible to loose yourself in it and become a prisoner of your own self. When I was younger I used to watch and read those kind of literature, the ones which are possible to become a prisoner of. Elves, dwarves, dragons, trolls. Yeah, and then, two years ago I went personally there in Iceland to check them out. Guess what? I realized I'd grown up. I don't believe in fairies nor elves nor ghosts. I believe in their ideal and in their glow. They'll always live in my child's heart, I'll tell my children their stories and I'll keep up with their loving secrets, but I'll no longer believe I'm among them being one of them, otherwise I'll be prisoned by my own lies. Fantasy is an additional brain not made to be an unique brain. Reality is out there for all of us.