Here is a really interesting job. It sounds really cool and it feels like a great chance and a great fit. Except someone else doesn't think so, it turns out. And so you get an email (sometimes), and they've gone in another direction. All the cool stuff you thought about, all the nifty ideas you had, are going to have to go somewhere else. Sorry, try somewhere else.
Is it personal? Did I talk too fast? Did I get my words mixed up? Did I answer something wrong? Do you feel like I'm a bad fit for some reason? No idea. There's no exit survey for job hunting, just a stream of "no" until hopefully you find a "yes" somewhere. It's a grinding, brutal, dehumanizing experience where the productivity and joy can be sucked out of you one sip at a time. The average unemployment period for someone in my industry is 9 months. The average unemployment period overall is 8.5 months. Two-thirds of a year of grinding, pulverizing rejection.
So what do you do? I know what I do. I don't know if it will work for anyone else, though.
I email friends, I let my partner know where I'm at. Because rejection sucks. But it's the thing you have to get through to get to acceptance. At the end of all the "no", there's a "yes". There has to be. I won't let it not be true.
Maybe I wasn't a good fit this time. But maybe next time, maybe at a different opening, maybe at a different place, I'll find a good fit.
That's how I feel today. Ask me tomorrow how I feel, and you'll probably get an essay on the cultural binding of worth and value and work, and how that makes me feel. But that's tomorrow. Today, I have to grind it out.