YC has more experience than you.
YC has more success than you.
If they turned you down, listen to the "why" and make the adjustments necessary to be successful.
Consider it a badge of honor that they even gave you the time of day. Take the information, feedback, advice, and rejection to heart and grow a pair.
Success is not static, it is dynamic.
So this is also the stage where many people hang their heads down and go back to their normal routine of nothing. But this is the only flaw in the YC system. It takes people who are not entrepreneurs and wholly dedicated to their idea and gives them an opportunity because they are a good hacker. Now once it gets to the interview stage they access how dedicated you are, but who wouldn't be at that point?
So please don't make some hugely dramatic post. Paul and Jessica would (and do) say that they are wrong about many startups. Not only the ones from interviews, but even with the applications. There are so many high-level applicants that it is hard to access who fits where.
YC has more success than you.