If I knew I could not fail

For school I wrote an essay about what I'd do if I knew I could not fail.
I think that this is a good topic; If anyone wants to do it with me they can.

Here's a small part of my essay:

    Although knowing I cannot fail would allow me to do so much, I still know that I have to fail. I know that one or two failures doesn’t mean a life of endless failure is awaiting me, it just means that I have an excuse to try again.

On failure: 
What are your views?
Is failure good or bad? Or is it both?
Can we learn from it? Can It help us?