We got rejected from YC several times and we are doing quite well despite it.
It really means little, unless you make it a big deal. Just move on. The magic you need to succeed is inside of you, not anyone else.
We just left the interview really confused about the reasons why they wanted to interview us in the first place. Since all they really did was arguing our market had 0 potential and our app was not useful, which in itself is totally fine. But why interview us, in the first place, if you don't believe in it?
The fact is, we will never know why they interviewed us and subsequently rejected us. We just need to carry on.
Our goal now is to get ramen profitable(we are really close) and prove them wrong ;)
If you really aced the interview, you'd never know it. They'd still dislike you. But they wouldn't be able to say no, since they knew they'd have to tell your advocate what happened in the interview--so they'd give you a "we'll get back to you." Then, later that day, the interviewers and the advocate have a huge argument on the real merits of your company. Your fate hangs in the balance of that argument.
If you've ever run a garage sale, you'll have seen this all play out in real-time on your lawn. :)
Despite what you think you saw in that meeting, you really have no idea why they rejected you (see Rashomon[1]).
And while writing this kind of post can be cathartic, you're also leaving behind an artifact that will be there to remind you again in the future.
You're almost better off just writing a draft post to get it off your chest, then deleting a few days later.