Struggling with my current WIP, I've been thinking about this very thing. So Chuck comes along, hammers it into eloquent words, and posts it on Facebook. Thought I'd share. Take it to heart, writers. 



"What is the issue that is eating you up? What is the personal fear that you can’t resolve and you can’t tolerate? Are you getting old with fucking NOTHING to show for it? Then, write Invisible Monsters. Are you worried that your brain or talent isn’t capable of creating anything interesting or unique, and you’ll die and rot and be forgotten – failing everyone you love? Well, then write Diary. My point is, use the story to explore and exhaust an issue of your own. Otherwise, you’re just dicking around, playing 'let’s pretend.' If you can be ruthless and honest about your own fear, you express something that other people can’t express. You can resolve your own anxiety – through research, discussion, experiment – and that freedom is what brings you back to writing.
What could you never talk about in a million years? Then, write about that." ~Chuck Palahniuk