For me, it comes in two flavors:
1) After I release a book, I realize that I shouldn't have, and want it back.
Usually it's too late for me to reclaim the book, but I have once or twice gone back to try to retrieve it.
2) After the book is released, I wish I had released it somewhere else.
Sometimes I go back and move it; other times I don't.
This evening, I released a book, took a photo, walked away, and then *almost* went back to move it to another spot, but I decided to leave it where it was, figuring I'd release a book in the other place another time.
When I checked on it two hours later, it was still where I'd left it...but by the time I got home to "officially" release it, it had been journaled.
So at least this time, it was good that I _didn't_ go back and move the book from its original release spot! :)