I have a kind-of chronic fear of manholes. At least the grate-style ones with big open holes.
It's not that I'm afraid of falling through them or anything. I'm just scared that something on my person will fall through the grate and I'll lose it in the sewers. Ipod, cellphone, house keys, etc etc etc.
My fear hasn't developed to the point where I avoid all manholes in the street. But I still grip everything I'm holding or that's in my pockets really tightly when I walk over them.
Yeah, I've got nothing better to talk about right now.