Way back in my early years of D&D, I started with the red box Basic Set.
Page B28 had an Example of Combat. Here's a small excerpt of the party encountering some hobgoblins. The party consists of four 1st and 2nd level characters . . . their fifth member having died in another example further on.
Silverleaf steps forward with both hands empty in a token of friendship, and says "Greetings, noble dwellers of deep caverns; can we help you?". Just in case, Silverleaf is thinking of the words he must chant to cast his spell [Sleep]
[snip some stuff about reaction rolls]
The largest of the hobgoblins shouts, in his language, "Go away! You're not allowed in this room!"
"It's okay, Gary sent us," Silverleaf answers.
"Huh?" the hobgoblin wittily responds.
The DM rolls a new reaction roll with no adjustments. The roll is a 3; the hobgoblins charge.
Picture me reading this as a nine year old. The editor of the book is a guy named Tom Moldvay, and even his name isn't on the cover. Who wrote this I wouldn't even have known.
So who the hell Gary was, I didn't know.
This only became funny years later when I connected the "Gary sent us" to Gary Gygax. By then I was playing AD&D and hobgoblins were Lawful Evil and no Good or Neutral player would never have negotiated with them.
A few things strike me about this example, years later. Things I'd like to see emulated in my Dungeon Fantasy play:
People negotiate with intelligent creatures. Not just bribes tossed to hungry monsters or a sword dropped to discourage a rust monster from eating your armor. They talk to monsters to try to avoid combat.
There isn't a big emphasis on slaying things for experience points. By the time I got to playing in a big way, and understood things like how to gain levels (we had a few guys at first level until it seemed like second level seemed appropriate) . . . we knew that you killed every freaking monsters you ran into and looted it. A properly "done" dungeon was empty of anything alive that was worth XP. The idea of exploring further and conserving resources by trying to deal with intelligent creatures who obviously won't be wealthy never even came up. The fact that this encounter netted the PCs nothing much beyond some information and a dead PC shows what could happen in combat.
Prisoners are taken and spared. I'm trying to remember last time that happened and it wasn't a group of lawful mercs that the PCs didn't want to kill to avoid pissing off other mercs. Everyone else got Black Company'd and had to dig their own graves. Heck, the example says outright that the Sister Rebecca "tells Morgan [Ironwolf] that a Lawful person keeps her word" - to evil humanoids!
So yeah, Gary sent us. He sure did, but as a kid I missed the joke and as an older GM we got away from "get some treasure out of this hole!" and moved to "kill everything we can to gain levels." Shame, that.