The question we writers are asked most often, the favorite question, is: Why do you write? I write because I have an innate need to write. I write because I can't do normal work as other people do. I write because I want to read books like the ones I write. I write because I am angry at everyone. I write because I love sitting in a room all day writing. I write because I can partake of real life only by changing it. . . .
(Orhan Pamuk, "My Father's Suitcase" [Nobel Prize acceptance speech, December 2006]. Other Colors: Essays and a Story, translated from the Turkish by Maureen Freely. Vintage Canada, 2008)
Regardless of what you write--fiction or nonfiction, poetry or prose, letters or journal entries--click on "comments" to let us know why you write.
For the complete article (revised and expanded), see Why Do Writers Write?

Comments
I write because my thought processes are a constant stream of “What if…?” Exploring and developing those ideas has filled collections, novels and a bunch of produced audio plays.
I write because I must. Spoken language is too immediate. The written word can be savored.
I write to discover. Writing is exploration. I love being taken on a journey that I don’t feel like I have to control. I never know where I will end up. Writing is still difficult at times for me, and I enjoy the challenge.
Writing and learning always fascinated me. I always struggled with writing, and felt inferior that I could not write well. But, as a retired senior and after a full life, I received my doctorate (Psy.D.) in Clinical Psychology eight years ago. Now, developing a writing career on the internet sounds exciting to me. Improving my writing, sharing my ideas, hopefully benefiting others can be a productive way to spending the rest of my remaining years.
I write because something strikes me, and then wonder what might come after.