Do you know what a personal "user's manual" is, and have you written one for yourself? I only heard such a thing exists as of late, and I realized that I had already written such guides in the past, but dismissed it because I assumed I was just being overly anal (snicker) about little details concerning myself. Some weeks ago, I started writing a real one in earnest and...it's tough. It's tough because you have to really take time figuring out how you tick, and even then tastes, tendencies, habits and quirks evolve and change. Despite that, it's something worth the time and it helps people understand you better.
Interesting idea. I think on a basic level it's an opportunity to state what you think, feel, like, dislike, and believe "at the time", and like previously suggested the manual can change over time. I think it would be interesting to compare the manuals every ten years or so.
There's something flawed about the concept, because the essence of life is movement, change and growth. Life and circumstances beyond our control forces us to change.