If fear paralyzes, maybe it's best used in bursts at times when you don't immediately need anything done and can spend some time on reevaluating basic assumptions. I wonder if there should be a genre of fiction that's analogous to horror except aimed at promoting epistemic paranoia. I've heard the RPG Mage: the Ascension cited in that context. I guess there's also movies like the Matrix series, the Truman Show, Inception. One could have an epistemic counterpart to Halloween.