Nothing speaks like a demo
Great post from my friend and co-worker Bryan Braun on the value of demoing.
It didn’t matter that his demos weren’t fully built, or available for anyone to use. We simply needed to see it, in order to understand.
I find this is true for any kind of project: hobby or professional. Feedback — that elusive crucial ingredient to a good product — tends to arrive when someone else can see/hear/touch/examine what you're working on.