Believe and act, as if it were impossible to fail.
— Charles F. Kettering
On the surface, one might think this is about work or doing something external to our inner selves (‘act’ as in ‘do some task’). But the quote holds true even for our internal endeavors. Another way of looking at it is, “believe and behave, as if it were impossible to fail.”
Or as Gene Kranz famously said, “failure is not an option.”