When you work really hard at something, and devote criminal amounts of time, energy and resources and still come up miles short, that sucks. There’s no sugar-coating it. That’s the bottom line: it sucks. Hard.
You’ll feel broken. How could you possibly do all that, engineer to perfection, and still fail over and over and over? Something must be broken.
You’ll feel exhausted, because it is exhausting to fall down that many times and still stand back up (if you even still can).
You’ll feel stupid and inferior. Usually when something doesn’t work repeatedly, it’s an inferior or ill-designed piece of equipment.
You’ll walk in endless circles. What was missed? One more time around, you’ll find it.
Finally, you’ll feel scared.
At this point I just want something to work. Anything. If path A is not meant to be, fine, I can come to terms with that and adjust my life, but you have to open path B for me, or C or D, I don’t care. I have to catch some kind of alternative, because I’m massively jammed up right now. If the alternative won’t present itself, I’ll force path unknown by just walking away.