I admit that I've never done this before, so it's hard for me to think of something. So I'll just make a list of the things I'm afraid of, because some of them are indeed confession-worthy.
1. Birds. Alfred Hitchcock ruined me for life.
2. Butterflies. I don't know why, but they absolutely terrify me.
3. Bees. At least I'm allergic to them, so I have an excuse.
4. Ladders. I won't even get up on a 2-foot-high step ladder. I've seen one too many cartoons where characters fall and end up in pain.