I was looking at it from the perspective of mental health. I guess it makes a bit more sense in the context of practicing a skill, though it's still not totally true.

This is simply and objectively false. Not every fallback is a "chance for success" or a "learning moment". Sometimes it's just a step back and you're no better or stronger for it later.

Not that one shouldn't try to stay positive but let's not peddle bullshit.