Writing in a journal to fix things that happened to you is a way to keep them from getting lost.
If you are a writer some of the notes might show later in your works and if you work with visual elements some might be incorporated in collages or other.
My notebooks are made the other way around.
First I make the artwork and only afterwards, sometimes years later, I start creating the notebook pages with elements out of these past artworks.
I admit, these pages don't exist in the real world and therefore breathe only in the magnetic field of my computers hard drive.
But in art you have to accept a fantasy for a reality and these pages are there because, like everytyhing else, we think it there.
I've been keeping a diary for thirty-three years and write in it every morning. Most of it's just whining, but every so often there'll be something I can use later: a joke, a description, a quote. It's an invaluable aid when it comes to winning arguments. 'That's not what you said on February 3, 1996,' I'll say to someone.
David Sedaris