Though the question is common, it actually comes (I believe) from several different mindsets. There are those who never read (sadly, a large percentage of our population, both now and historically) and thus cannot grasp why anyone would bother to write novels, short stories, or fiction of any kind. Then there are those who understand, correctly, that it is nearly impossible to make a living as a full-time writer and therefore wonder why that time at the keyboard isn’t spent instead at something that would be more financially beneficial. Finally, there are those who do read, don’t know or don’t care about the financial part of it, but do understand just how difficult it can be, perhaps because they have tried it themselves.
The answer I often give is a flippant one (no shock to those who know me): I write because the voices tell me to. This usually creeps the questioner out enough that they simply move on, but in a funny way it’s true, for me at least. My characters talk to me, not in some schizophrenic “hey, go grab that chainsaw” way, but in a “we have a story to tell” way.
That, in reality, is why I write: I like stories, and I feel like I have stories to tell. Hell, we all like stories, even when we don’t realize that’s what they are. Obviously novels and plays and movies are stories, but so are paintings and sculpture and music and dance. Story is everywhere.
It has been said that writers create new worlds because they are dissatisfied with the real one. I get that…I like my characters a lot more than I like most “real” people (except for you, Dear Reader; you are amazing). My hope is that in some small way the world I create on the page will have a positive impact on the world beyond the page.
There is another, more selfish reason I write, and it has nothing to do with money: immortality. Carlos Ruiz Zafon summed it up quite well in his novel The Angel’s Game:
“A writer never forgets the first time he accepted a few coins or a word of praise in exchange for a story. He will never forget the sweet poison of vanity in his blood and the belief that, if he succeeds in not letting anyone discover his lack of talent, the dream of literature will provide him with what he covets the most: his name printed on a miserable piece of paper that surely will outlive him.”
So to sum up, I write because I like stories, I want to change the world if only in a small way, and I want a part of me to live forever. There are worse reasons to get up and bang away at a keyboard at 4 in the morning.