Good thread. As I read it through I kept on wanting to say something about some point - and a couple of posts along and someone else had done it for me.

One sentence that leapt out at me was when Tim Leaning wrote: "I do have a habit of assuming the the person who just performed a song I never heard before had written it."   Because that's exactly what I find myself doing.

Anyone else ever have the experience of not being sure whether they changed something in a song or learnt it that way? Or for that matter, whether they wrote a song or learnt it from someone else?

I think faulty and failing memory can be a key element in the way songs get knocked into shape.