What's the most horrific thing you've discovered while you kicked the dust and rattled the cages of your own memories -- which you've gone on to use in writing?
On a deeper level though, I think the thing I tend to learn more about me as I write is just how much growing up the child of divorce affected me. I remember when I wrote the story "Erosion" (originally published in O' Georgia, currently collected in Gomer and Other Early Works), I surprised even myself when the last line spilled out onto the computer screen: "He was a much smaller man that I had realized." It was almost cathartic. I hadn't realized myself the depth of loss I had been feeling having grown up without a regular father around (I had a few step-fathers, but not a steady ongoing dad, until I was 15). I think, in many ways, writing that story helped me deal with my feelings about that loss (regardless of blame), and move on to actually begin being able to have a real relationship with both my dads (my step-dad of more than half my life now and my natural father who sired me). I'm luckier by far because of that, but dealing with it within the confines of that story wasn't easy or fun.