I think there's two very different kinds of failing. They can mix with each other, and often do, but they're very distinct.
In one case, you take a shot at something and it just doesn't work out. It's a certain soreness, to do your best but come up short. I can get used to this pain, much like working a muscle. It always stings, but the way I feel about it changes. The challenge is there, I have more to work on, more to reach for. The pain comes from learning, knowing what went wrong and why, knowing what to change.
In the other, you simply don't capitalize on the opportunity. It's rot that comes from rot, time passing by. An object at rest stays at rest, and inaction begets inaction. Nothing changes or improves, and that's because of me, too.
Both are fine, both teach their own lessons, both are acceptable and understandable and forgivable. But I'd rather taste the heat of defeat one thousand times than regret letting a chance rot away.
No matter what, it's ok to fall. I just need to get up again.