Human beings have a helpful but unhealthy built-in defense mechanism. We're programmed to prime ourselves for danger. Prehistoric Man used this to fend himself against savage beasts. Nowadays, we use the same mechanism to guard against much less exciting things. You needn't prime yourself in ways you believe. The savage beast you're anticipating is unlikely to spring from bushes and even if it did manifest, it's likely to be more of a kitten than a saber-toothed tiger.