Although most writing is a lot of work, there is one time when it really is fun. That's when you've basically written the first draft of the story and you can see that the structure is right and the story more or less works. At this point, the pressure's off. You've done all the grunt work of nailing the canvas to the frame. Now you can start painting on it, which is to say relax, let the creativity flow while you add the subtle touches that make a story go from from being a mere narrative to a real story.