Every emotion is based off of the primitive self. Humans had to survive during our initial development in prehistoric times. Instincts and sensations told people where to find food and build shelter. Fear gave people the ability to make smart decisions. Nighttime, for example, was a time to hide and rest because we couldn’t see our predators in the dark. This fear of the dark is actually self-preservation in its rawest form. People survived and evolved by using their fears to guide their decisions. You don’t have to fear daylight because you can see dangers lurking with clear eyesight that focuses several miles out to the horizon.