Chuck Palahniuk, author of such groundbreaking works such as Fight Club, Choke, Romance and Snuff, recently did an AMA (ask-me-anything) on Reddit.
At one point, replied to question "What is your biggest source of inspiration when planning a new novel?" as follows:
To begin a new novel, I look for the biggest problem in my life that I can't solve or tolerate. Something that drives me nuts, but I can't fix. Then I find a metaphor that allows me to explore the problem, exaggerating and expanding it beyond reason. I build it up to the worst scenario possible and then find a way to solve it. By the time the book is done, I've exhausted all of my emotions around the original problem. Whatever it was, it no longer bothers me. And typically, during the time of writing, the problem has resolved itself. It's like magic. Try it. It will keep you alive in this world of bullshit.