When it comes to failing remember one thing...

I don't put failing and rejection in the same category. Failing means you couldn't accomplish what you set out to do. Rejection means that someone else doesn't believe enough in what you're doing to bet on you. It could be a failure to communicate on your part, but it could also just be something else completely random, especially when you're talking about a highly selective accelerator like YC.

To me, rejection is almost a non-event. If you're doing something worthwhile, you're going to see a lot of rejection. Not everyone can get on board with what you're doing. That's okay. Other people will get what you're doing and believe in you (unless you haven't shown anything... gotta give folks a reason to believe in you, after all).

That said, I understand your point (learn. move forward.) That much I agree with.