The Stories Within.
Lots of people over the years have said to me, when they found out I was a writer, "Oh, I've got a great story for you to write!" I'm always shocked - though you'd think I shouldn't be by now - that people think I need help finding tales to tell.
One of the things about needing to be a writer is that there are stories inside that are constantly pushing to get out, and one of the best things about being a novelist is using the imagination to create new world and new lives. Writing someone else's story would be like repainting a watercolor. There is an art to retelling someone else's story, but it's very different from inventing your own.
The hard part for me isn't coming up with ideas, it's making those ideas gel into form, getting my characters to take on a life of their own, and then getting them to let me tame them a bit to make the plot work.
On the same note, when I was a beginning writer, I often found that creative writing classes focused on accessing your inner creativity to dream up stories. This was always frustrating for me because I had all sorts of ideas running amok and just needed to learn how to corral them; I needed the techniques for good story telling, and info like: how not to overuse commas - which I think I still do.