More important, why is a 2-year-old even more scared of these things? Why do 2-year-old children cling to their parent’s legs? Why are they “hyper-aware” of their surroundings?

Because biologically, 2-year-olds need to be scared. Their lives depend on it. Their young systems need to be alarmed and say, “Whoa, buddy. Stay close to your mom. This is not safe.” And even though your son is showing signs that he is intelligent, he is still immature. He cannot look at a slide or ride and say, “Get it together. This ride has been inspected and is thoroughly safe. Get over your fear and get up there!”

Source: A toddler is scared of everything. Should his parents be scared of that? – The Washington Post