[Michael.SF.]

One thing that really gives me the willies is walking across an open grate. The idea of being able to look through what I am walking on is too much.

[DUMBGRUNT]

—”One thing that really gives me the willies is walking across an open grate. The idea of being able to look through what I am walking on is too much.”

In farm country, they use open grates to keep the livestock inside the fence.

On my bicycle, they made me nervous, a few times I walked it.
Our dogs never liked them but would cross, but not on anything that moves in the slightest.

https://en.wikipedia.org/wiki/Cattle_grid#:~:text=A%20cattle%20grid%20%E2%80%93%20also%20known,horses%2C%20or%20mules%20from%20passing