It's a lot of work that goes into these applications, and I absolutely don't sweat the rejection (hurts a little, but that's all right, we're not in the business of passing the YC application), but as a future suggestion maybe — and I absolutely understand YC gets a ton of applications — if there was a way to just get a short comment on why an application was rejected, it would be so incredibly helpful. One sentence, perhaps even just a standard tick-box canned-response the reviewer hits at the end of reading it ("market-fit not clear", "worried about team", etc.). No interest to argue about it, but the value given back to startups would be tremendous, with very little time required (ticking the final rejection-reason box, even if it just says, "not really something I'd be interested in").

I would even pay for it. I know that's absolutely not within YC's context and mindset, but I'd pay to just read one short line that helps us see what you saw (or hoped to see but didn't).