Someone asked me if I self-published Fairy Tale Fail because it was rejected by my traditional publisher.
The simple answer is: No, it wasn't rejected by my publisher.
The more complicated answer is: It wasn't accepted either.
What it was, for a time, was a pitch email with attachment that was floating around without a yes or no. And then I discovered that I could sell it as an ebook on Amazon, so I went and did that.
I guess the context of the original question was, "Should I self-publish instead? Why go through the possibility of being rejected by a publisher?"
You can't avoid rejection, sorry. Maybe for a self-publisher it doesn't come as a letter that begins with "We regret to inform you..." but you can still experience:
1. Negative reviews
2. Lackluster sales
3. People who tell you they won't buy your book because they don't like the format/genre/don't read at all
... and many other reasons.
I happen to think that you should independently publish because you want more control over the publishing process. NOT because you just don't want to experience rejection.
In fact, rejection can help. Not just for the writing part, but the publishing as well. Maybe you can't go back and rewrite an already-published book to make it better, but you can apply those lessons to future work. And as a self-publisher, you can change up your pricing, covers, availability, and other things to make sure that certain people give you a chance.
Oh, and this year, my publisher offered to distribute Fairy Tale Fail in paperback, so it will finally appear in local bookstores soon. So, yay! I consider that the opposite of rejection.