Afraid of losing ourselves
You and me, as conscious beings, we're special. We don't just move in the world, acting and reacting--we know we're here. We have selves (illusory as they may be). We are conscious of our existence. We also know we're not here forever.
"Every creature has fear," said Jared. "Even the non-conscious ones." "No," said Boutin. "Every creature has a survival instinct. It looks like fear but it's not the same thing. Fear isn't the desire to avoid pain or death. Fear is rooted in the knowledge that what you recognize as yourself can cease to exist. Fear is existential."
--- The Ghost Brigades by John Scalzi
You and me, as conscious beings, we're special. We can be afraid.