I got a query reject today on a novel, but it came with a small critique. That's always a bonus, and it's clear the editor read the sample chapters and thought about them. Some of what she said makes a lot of sense. Some is--well, some is really off the wall. I won't go into details, because I think ragging on rejections, especially personal rejections like this one, is unprofessional and unbecoming.
The really good thing about any critique, though, is that no matter how off-topic it first appears, it's a good jumping-off point for rethinking problems. This critique got me thinking about one of the book's main characters and how I can flesh him out a little. I find that the best way to round out a character is to let him or her talk. So I've come up with a scene where that character can talk to the other MC. It may end up too long or too boring, but I can trim it down to its core later.
And then, while I was thinking that new scene over, I started thinking about an earlier scene, and realized I'd left out a wonderful opportunity to show an aspect of the character I hadn't even thought about. And I thought I knew all about him.
So sometimes a rejection is a good thing.