I don’t offer much advice on this blog because publishing is such a broad industry. And there are so many changes happening these days most advice anyone has to offer tends to become obsolete a month later.
But there is one thing I can advise that I’ve learned through experience when it comes to getting rejected by literary agents. And that’s very simple: just delete the rejection and move on. There’s no need to send back a nasty e-mail (no matter how much you want to), there’s no need to defend your position, and there is no reason to take any agent rejection personally. They don’t know it all, and the best agents will be the first to admit this.
So take all rejections for what they are: a subjective opinion. If an agent takes the time to offer comments with the rejection and you agree with the advice, there’s nothing wrong with thanking them. But if an agent rejects you and makes comments you don’t agree with, there’s no need for you to comment. Just move forward and put it behind you.
Always keep it positive. Trust me, the next day you’ll be glad you didn’t reply with a nasty, counterproductive e-mail.