I like to know the big picture.
I can handle details, complexities, and even ambiguity. But I need to know where I'm going. I need the frame first. This was especially true in school. If a professor started a lecture by stating the main goal for that day, I was in. When they would use examples first, then ask the class to draw conclusions, I got antsy. Just tell me where this is going. This lead me to think I'd be a total plotter.
At the same time, I'm a bit of a spontaneous person. Not wild or impulsive, by any means. But, in my natural element, at a gut-level, I don't like being tied to a rigid structure. I like to be able to adapt, especially if I get new information. Sometimes that manifests as a late-night trip to Target. Sometimes it means I'll let the kids have a sleep-over when they ask at 7pm. See? Pantser qualities.
So when I started writing I (thought I) knew the general frame of a romance: meet, smoulder, conflict, sexy times, more conflict, crisis (The Big Misunderstanding, Being Kept Apart by a Big Bad, for example), crisis resolved, and HEA. In putting my ideas together, I roughed out an outline and then started typing. Along the way, I'd been reading several books and blogs on fiction writing, and romance in particular (topics I'll cover another day, with links). Back and forth, I've been planning and writing, discovering ideas that work, and some that don't.
I find I'm between both worlds. I plot and outline and even created what Blake Synder in Save the Cat referred to as "The Board" yesterday. (Woo!!!) Sometimes when I just put butt to chair and write and write and write, new ideas evolve, problematic elements find solutions. I tend to believe you need to do what works, and right now, this hybridization is working for me.
Which style works for you? Does it depend on the book or project? Is your writing style in sync with how you approach other areas of your life?