Dungeons ?
The principal hurdles to ENJOYABLE dungeons have been...
1) MAPPING: resolved by just throwing the map on the table ; mature players will not metagame the contents, and it avoids endless descriptions of length, width, etc
2) GOAL ORIENTATION: you need a precise reason or a developing cascade of reasons to be there. Given objectives, players stay focused
3) CHARACTER LEVEL: dungeons are rarely a stone throw away from a usable base camp / town (you can have an exception, but such should be rare). So the PCs need to have commensurate levels to deal with travel challenges.
I'm sure I could find other issues we have resolved over the years
Dungeons are indeed a controlled environment, and a milieu filled with unknowns. Compare that to a town or city where one or more PCs have spent their entire lives (the preparation could be mind-boggling)... Either have a hand-out with a lot of detail prepped before game (at least a week) OR hope you have inventive players who can become assets in a "collective creation" mode > the player will state "I go see that fat old winebag Tharkesh, captain if the militia, in his usual hangout, The Intrepid Fey".
That method only works if the players know the style and tenor of the campaign world ("I go off to Wally Walm, Artful Crafter of Quasi Free Items" wouldn't work)
The principal hurdles to ENJOYABLE dungeons have been...
1) MAPPING: resolved by just throwing the map on the table ; mature players will not metagame the contents, and it avoids endless descriptions of length, width, etc
2) GOAL ORIENTATION: you need a precise reason or a developing cascade of reasons to be there. Given objectives, players stay focused
3) CHARACTER LEVEL: dungeons are rarely a stone throw away from a usable base camp / town (you can have an exception, but such should be rare). So the PCs need to have commensurate levels to deal with travel challenges.
I'm sure I could find other issues we have resolved over the years

Dungeons are indeed a controlled environment, and a milieu filled with unknowns. Compare that to a town or city where one or more PCs have spent their entire lives (the preparation could be mind-boggling)... Either have a hand-out with a lot of detail prepped before game (at least a week) OR hope you have inventive players who can become assets in a "collective creation" mode > the player will state "I go see that fat old winebag Tharkesh, captain if the militia, in his usual hangout, The Intrepid Fey".
That method only works if the players know the style and tenor of the campaign world ("I go off to Wally Walm, Artful Crafter of Quasi Free Items" wouldn't work)