I am a very free-spirited person. I am self-employed, I don't like being under anyone's thumb, highly independent etc. That being said, I still need structure, and struggle a lot when I don't impose some forms of structure in my environment. When I started working on being more organized, I definitely became happier, because there was no longer stress due to the lack of a properly working space, feeling overwhelmed etc. Clutter is chaos and it does have an effect on the psyche whether we like to admit it or not. I'm no Martha Stewart or anything and never will be, but I am organized enough to know where things are. I put things away immediately as they are used etc. and it has improved my overall sense of well being a lot.
Ironically, organization is very liberating to the spirit - not stifling as we tend to view it :)