I think the most surprising thing I've learned about writing isn't about writing at all. It's an insight into myself and the way I see the world. I have long known that I'm a thief rather than a true creator: I construct my fictional worlds and characters from bits and bobs that I gather during my real life. These odds and ends have taught me about what I value in the world, and I've now written enough novels that I can see a pattern to the things that catch my eye.
Writing has taught me that I look for the black sheep. The exception to the rule. I am interested in patterns and society but only as a backdrop for the people, events, and objects that don't fit into it. I don't so much mind whether it is a positive outlier or a negative one, only that there are few other pieces in the puzzle that match it.
I suppose I always knew that these outliers interested me as a reader, and it follows that they interest me as a writer. But it's only recently that I realized that these are the things that interest me as a human as well.
Now that I've learned that about myself, I'm presented with a host of questions to ponder: What do all of these black sheep have in common, if anything? What else have I discovered? Can I use what I've learned about these unusual people and things in my books in real life?
Ask me again in 10 years and I might have an answer or two.