In Star Wars (Lucas loved Campbell and the hero's journey), Luke tells Yoda that he feels the dark side emanating from an old cave in the swamps. The wise mentor told Luke that he should enter the cave, and that the only danger of the cave was whatever Luke took in there with him.
The popular belief is that the cave represented all of Luke's fears, or our fears, and this was about facing your fear. But I posit something different. What if the cave is just a hole in the ground, and what the hole is 'filled' with is you. Luke took his lightsaber in with him, a weapon of defense. He went into the cave looking for a fight, and so he got one, with himself; or at least a version of himself that he feared could come to pass.
And I think that's the crux...the cave is just a cave, unless you make it something more. It's speculation of our own fear that fills it with our enemies. Just like we judge someone in the blink of an eye, we've assumed the cave without ever stepping into it. Given it all the power in the world to frighten us, and we haven't even darkened its doorway.
Thoughts can't hurt us, but they can stifle our ability to progress. What we're really battling with is uncertainty; and until time travel or future reading comes to pass, we will always be uncertain no matter how measured, prepared, or strong we become. Still, we must find a way to believe in what cannot be measured or seen — The future.
We must be brave enough to dare. Dare to be, dare to want, dare to lead. We have to 'be' in the Arena to fight anything, so let's get in the arena first, and then fight if we need to...otherwise,that particular cave is not a place we need to go or think about. It's just a fucking hole that we don't need to fill.