Things That Worry Me Which Probably Shouldn't

I hesitate to walk over manhole covers or those trap door things in the sidewalk, not because I'm afraid I'll fall through, but because when I do fall through I know I'll end up in a secret subterranean world, and I just can't keep a secret.
   There are many things below ground, phone lines, water pipes, cable TV cables, sewer pipes and the C.H.U.D.s that live in them. But I'm pretty sure that there's more, a hollow Earth maybe, or just really big caverns where blind cavefish have developed a some sort of civilization where there's no shame bumping into walls.
   It would be my luck to fall into the one manhole that doesn't end up in the sewer but ends up in some barbaric, Edgar Rice Burroughs-inspired world of dinosaurs and psychic flying lizards. I'd inevitably get captured by the psychic flying lizards, who would set about planning to kill me in an absurdly round-about way. I'd get out of it by explaining to them that no one on the surface world would possibly believe me if I told them what I saw, but I would assure them that I wouldn't say anything in the first place.
   Because the psychic flying lizards are gullible (right? everybody knows that) they would let me go. Then, of course, once I was safely back on the surface world I would blab the whole thing to anyone willing to listen.
   Before too long you'd have developers moving in, clear-cutting forests of giant ferns so they could put up condos, displacing the dinosaurs and buying the psychic flying lizards out for pennies on the dollar. Then the gorilla-men would go next, and the sabretooth-men, and finally the Stone-Age type human beings would start walking around with cell phones discussing what they'd seen the night before on TMZ.
   See? It's just better for everyone concerned if I walk around metal plates in the sidewalk.