I have my favorite stories. Favorite ones to read, and favorite kinds of ones to write. Writerly preoccupations, literary kinks, bright copper kettles and warm wooly mittens. There are things I am always going to find fascinating, new favorites that will get added to the list, old preoccupations that will fall away when I have finally said what I needed to say about them.
These things are fun (for values of fun that include "compulsion" and "agony") for me to write about - there is a need I have, to tell these kinds of stories about these kinds of things. The problem comes, for me as a writer, instead of just a person with a consuming interest, is when I love one of these favorite things too much.
The problem is that characters can't be both perfect and real, and a story in which nothing new happens is not particularly interesting to read. The problem is, when I love something or someone, I don't want to look for the places that aren't perfect, and to write about them, I need to. When I love a story, or a character, I don't want to do violence to it, to cause pain, to write the sadder and better ending.
But that's the thing. Sometimes perfection and happy endings are lies, and it's my job as a writer to tell a kind of truth. It's more important for me to tell the story, and to tell it right, than to maintain that false image of perfection in my head.