I don't know about other folks but I absolutely love watching other people's sketch books.
It may sound odd, but in these sketch books,
among these sketches and drawings of ours that we often despise as "second grade...", THERE we often find the most unique ideas when we preview them later, after some time.
In my opinion, these sketch books are the most VALUABLE property of every artist or hobby-artist.
There is a real treasure hidden even in the simplest sketch, which we often aren't able to recognize when it actually comes out on the paper.
I encourage EVERYONE, please KEEP your sketch books and refer to them from time to time, you'll be surprised what you'll find. It's almost granted that the gold is there.