I like to think of my plot maps and outlines as my safety net when I am writing. I can always check them to make sure that I am on track to hit all the key elements of the story I want to tell. They give me a feeling of security and make me more comfortable with the story. It is something that I find very gratifying and soothing. (Much of my writing comes with thereputic qualities for me.)
Sometimes, however, I write with out that safety net. I can not say that one method is better than the other on the terms of what is produced. I may be more comfortable with that safety net, but some times you have to do the uncomfortable thing to grow. I make it a practice to put aside time to write with out a plot all planned out. In that writing session, I follow the story as it develops. It becomes something like what a famous Ray Bradbury quote once said, "Plot is the footprints of your characters in the snow on their way to adventure." (I'm not 100% sure I got that quote right, but you get the feeling.)
It is sometimes exhilarating to be writing with out everything planned out. It is like riding a roller coaster and you have so many plot twists you suddenly come upon. It makes you a little giddy, a little dizzy, and maybe a little sick. I have days where I seek out that excitement because I'm tired of the stately pace of plotted work.
It is sometimes horrifying to be writing with out a net. You may find yourself struggling to come up with more material to continue the story. Or stuck with out a consistent thread to tie all of the work together. It may turn into jumbled stream of consciousness writing that lacks any logic and fails to tell a story. The efforts to wing a story may turn into something that you want to shove into a draw and refuse to acknowledge it ever existed.
In both cases, however, something valuable comes out of it. You gain more experience at your craft. You become stronger at coming up with plot elements and recognizing when phrases fit together right. You learn to relax your strict standards for the sake of telling the story. And you come away with the evidence that you can do this with out your safety net. It may not be much but this strengthens your confidence as a writer.
The wonderful thing about this is that you don't have to share your literary experiments with the world. In fact, it is a good thing to keep a separate place where you do your written experiments that you have complete control over what anyone sees. Making the act of literary experimentation a private thing, you give yourself the freedom to write badly with out any criticism. Regular forays into new and unfamiliar ground with writing techniques helps to breathe greater life and depth into your chosen work.
Screw your courage to the sticking place and do that high wire act of writing with out that net. You may fall, but you may also fly. And unlike a real high wire act, you don't have to worry about injuries after that fall. In the end, it is all a learning experience. And learning experiences are good.