I crossed the 60% mark on the rewrite of my second novel. I wrote the first draft what seems like a billion years ago as a way to cope with a particularly bad time (it was actually six years ago).
Rewriting such an old draft is an interesting experience. I discovered two things about myself by reading it.
First, I've found a picture of my old self, of the man I was and of the pains I lived at the time (the entire book is a gigantic allegory, after all). It is a fascinating experience to see that, even if it doesn't feel like it, I am much stronger than before. Sure, there are a lot of small things that are still the same (I am a perpetual work in progress). But in many other aspects, I've improved as a human being.
Second, following the "invisible progress" trope, I can see that I am a way better writer than I was six years ago. I'd like to show something I wrote recently to my old self and tell him: you suck, but you will be better—it will get better.
I can't, of course. However, in another six years I may have the same feeling. So consider it "message received," future–me.