I've always found it easy to come up with stories, but I've lost practice to an alarming extent and now that I'm trying to write again, it is a disaster. I love when I can write a whole story in one go - and they tend to do better than stuff I meticulously work on for a long time - but I did get more planner-y as I went, too. My outlines are half outline, half nonlinear writing, though.