what is your greastest fear?

Oh, I'm afraid of things going under my finger nails, or either them being ripped off somehow. Oh my, that just makes me scared talking about it. I'm also sort of afraid of the dark but not really. Its when i'm not feeling safe, I start to wonder if something is there or not. If i'm tired, or happy, I don't even bother to think if something is there, I just go to bed. I remember watching horror movies when I was younger. So, the thought of something being under my bed sometimes still lingers there, but I don't check it cause I know its an unreasonable thought. I'm afraid to get on roller coasters, I got on one once, I love the thrill of being scared, but I don't want to be scared at the same time. Everyone naturally wants to be safe even if they find it fun to be scared.