Yes and also Force-user aside, fear of life/failure is a good source of motivation and keeps you from doing something stupid. Vader and Palp believed they could rule by making others fear them, yet the fear makes those others stronger by giving them motivation, Force-user or not. Need a balance of fear and courage, not too little fear and too much courage so you won't be reckless or vice versa, they keep each other in check. As long as you fear the right things, and not some nonsense phobia of an unreal danger.
Rage is a good motivator when you need brute strength, but it also makes you stupid and reckless. Think fear is better to draw on, though feeling fear itself is uncomfortable.
On the downside of drawing on fear for power, if you stop fearing your opponent you become weaker.