As a player, yes I have lost the dungeon. My characters keep looking for them. They go up to random NPCs in a town and ask,"Hey buddy. Where's the nearest abandoned castle built by a crazy wizard several centuries ago which is now overrun with strange and terrifying monsters but still full of treasures beyond the ken of mere mortals?". The NPCs give my character weird looks and walk away, then the DM throws a book at me and tells me to get back to writing my 15 page character backstory due by the end of the session.
Of course, I make up for that by putting lots of extra dungeons in my campaigns. The PCs in my campaign can barely walk around without tripping over or falling into a dungeon entrance.
Despite the fact that my players seem to really enjoy the dungeon-ful campaigns I run, they never seem to create the same type of campaign when they GM the games. IMO it's a culture thing. There's so much anti-dungeon prejudice out there that people who would otherwise hearken back to the good old days of 10x10 rooms choose not to because they're afraid the "real roleplayers" will mock them as unevolved, rollplaying boobs.
Terms like "mindless hack-n-slash" just prove my point.
The only "mindless" thing about the play in my campaign are the undead who will kill your character and eat his brains if you're not paying attention, playing smart and treating combat as a last resort option.
--EN Worlder Ourph
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