Many feel like that, and I understand your plight...I really do....but it does matter what your stuff looks like, it just does. I also understand how overwhelming the process of purging and restructuring your life is. My greatest design advice is to take a moment...breath....and enjoy the process. Remember no one ever died from choosing the wrong throw pillows. Choices for the most part can be edited, so hopefully that will take the angst off of the process.
If you want some instant gratification start with the livingroom...this is a great weekend warrior project! Take inventory of what you have and then get a few new pieces to update your space. My greatest tool is the almighty throw pillow, this is an inexpensive way to introduce texture, whimsy, and that punch of color. Throw pillows can breath life back into a boring neutral sofa, and can update the entire look of your living room. A throw pillow could also serve as inspiration and a starting point for your living room redo. The pillow fabric dictates a style and color scheme, pull from that to choose wall color and accents pieces.
Have fun with it, buy a few different patterns and colors (coordinate not duplicate)..and if you don't like them you can return them, no lives will be lost...I promise.