Living in someone's shadow, like Robin is in Batman's (until teen titans came along)?
I know some things that would break me as a person, but I don't actually fear them happening because highly unlikely and just kinda thinking about them just doesn't bother me.
But things that do scare me are sharks, specifically dreams of being in the water with them. FU megalodon. As an extremely proficient swimmer by human standards and having been hooked to pbs and discovery channel as a kid and teen, I know exactly how fucked we would be if a shark really wanted to eat somebody.
And heights bother me. I get scared/anxious every time I have to jump out of an airplane, but once I feel that parachute catch wind and start deploying I get to start enjoying it.
And those are really the only pressing concerns/fears for my part.