Don't look this gift horse in the mouth. A lot of people do, apparently, based on this article: Slushkiller. It's a very long article, but I recommend you take the time to read it. One of the most important lessons I took from the article is that of perspective: don't take it personally (really). Too often writers have completely the wrong perspective when we look at rejection notes. This is ironic, because writers are supposed to be really good at seeing the world from different points of view, and distilling these perspectives into captivating prose.
Here are a few choice quotes from the Slushkiller article, to give you a flavour:
What these guys have failed to understand about rejection is that it isn’t personal. If you’re a writer, you’re more or less constitutionally incapable of understanding that last sentence, if you think there’s any chance that it applies to you and your book; so please just imagine that I’m talking about rejections that happen to all those other writers who aren’t you.
I frequently see denunciations from writers who say an editor can’t possibly judge their novel from three chapters and an outline. Sure we can, even if the chapters are short and the first one’s atypical. In many cases, three pages are enough. You don’t have to drink the entire carton of milk in order to tell that it’s gone bad.So, don't take rejections personally. Glean and learn from them when you can. Keep writing, keep submitting, and you know all you need to know about how to get published.