system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does fog seem to move around me, without me ever going "into" it?
gpt
Fog is mostly transparent.  No matter where you are, there's only a little bit of fog inbetween you and something right in front of you, so you can see it just fine.  If you're looking at something a hundred feet away, then you're looking at it through a hundred feet of fog - even if it's mostly transparent, lots and lots of it still adds up, so it's tougher to see the object.

It's the difference between looking through a single piece of plastic wrap (which looks clear even though it's only "mostly" clear) vs. looking at a roll of plastic wrap (which looks opaque since it's hundreds of layers deep).