I am as interested in seeing what happens to my characters as any reader; that is why I tell kids that writers write for the same reason readers read - to find out the end of the story.
We don't notice that our cells are turning over all the time. You get a completely new composition of cells every seven years, and on the surface, or subjectively, it looks as though you're the same for seven years. It's like a ground - it looks stable, but beneath it, everything is shifting all the time. It's exciting and dangerous.