Yeah I think we all have that little voice at some point that goes what it atoms aren't real, what if things are exactly as they appear? What about germs? What about the "globe"? What about "other" ""people"" and— and then you think about it a bit and it unravels very very quickly, but it's good to be able to throw your entire mental model into doubt sometimes.
I wonder if some people aren't able to build a satisfying mental model for some reason. I don't think it's just a matter of intelligence either, but something more emotional.