The privacy settings were carefully designed to have vague wording that how they worked on the surface wasn't how they really worked. Each and every one of them which had a different functionality than what the wording suggested on its surface resulted in you sharing to a much wider audience than you thought you were.
I recall carefully testing it out with a burner account which my main was not friends with, and it consistently taking 2-3 tries to get the privacy settings back to where I wanted them to be.
I would take those days over what Facebook is today - which is to say, useless. The only thing I use it for is groups, which have the good sense to only be about the thing you want to learn about when you look at the group. Still though - it is sad that FB Groups killed off small web forums.