Earlier quoted context omitted.
Sounds kind of like you're disguising your YC-denial under a veil of "I've done this before, and I'm better than you" type of thinking. Are you sure that's productive? What was your successful execution?
When you're rejected, you can interpret it as this "says something about me" and take it personally, or you can interpret it as an opportunity someone else missed out on for whatever reason, (not a good match, not web 2.0 enough, who knows!) and move on. If you believe in your idea and yourself strongly, there's usually only one clear interpretation you should take. And yes, self confidence is generally a productive…
I think my idea is great.
It's more of a "can I do anything to improve". I believe in always trying to find ways to be better. If my idea was rejected because they thought it was too niche, I would want to know. If it's because I couldn't think of other things I've done, I'd like to know. etc, etc.