"I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain."
"The mind can go either direction under stress --toward positive or toward negative: on or off. Think of it as a spectrum whose extremes are unconsciousness at the negative end and hyperconsciousness at the positive end. The way the mind will lean under stress is strongly influenced by training."
The Fremen were supreme in that quality the ancients called "spannungsbogen" --which is the self-imposed delay between desire for a thing and the act of reaching out to grasp that thing.