Quote from : Doctor Who: The Stealers of Dreams Book

The doctor will tell you that all fiction is harmful, that the pleasure we find in good dreams is more than offset by the terror when those dreams go bad. I say even the bad dreams are good for us. There's something alluring about monsters, about things that hide at the foot of your bed and go bump in the night. If there weren't, we wouldn't dream about them. We want to experience that thrill, taste that fear. There's nothing wrong with a healthy scare. It sets our hearts racing, unleashes our adrenalin, lets us know we are alive. For after all, what could be more exciting-more stimulating- than tackling those monsters head on. In our dreams, we can do that, we can have that excitement, and yet be protected. OUr dreams can't hurt us.