When our ancestors heard rustling in a nearby bush, they either approached the situation with caution or acted like a typical sorority girl in a slasher (“What was that noise? Let’s go look!”). The latter was sometimes killed by whatever was in the bush, and the cautious survived, passing the trait of being a big wuss down through generations. So it’s not my fault I’m afraid of spiders, you see.
Anyway, that has had unintended evolutionary consequences. We’re hardwired to react negatively to anything relatively new. That’s why bad news sells, and the thing we fear the most is the unknown and unknowable.