There are lots of stories that my friends swap about playing Dungeons & Dragons in the old-school style. In the hope that Wizards of the Coast has managed to bring new people into the hobby I'm going to speak of a few things that I encountered while playing D&D back in the late 1980s. I wouldn't quite describe my old friends as grognards but they have described similar experiences to me.
One of the Dungeon Masters I played under was particularly stereotypical of the old school method. Mitch (his real name is Robert Mitchell) did everything to extremes. His games were powered up over standard rules but he just made all the enemies that much more difficult. Mitch had fallen for the illusion of power.
legalzoom.com) so that their DM couldn't twist their request because of all the clauses and stipulations. The DM giveth and the DM taketh away.
Another type of story about old school D&D, that I experienced directly on multiple occasions, is the thief character that scouts out the enemies. The thief goes in ahead of the other characters to get the lay of the land and give the party information to plan their attack. The key to this old school trick is that the thief steals some, or all, of the treasure while he's sneaking around. The other characters never know about this. The fighter does all the dirty work, for the lazy thief, of killing the monsters and advancing the party through the dungeon but he gets much less treasure than the DM or modules place in the adventures. Some may have never heard of this behavior from the wild west early days of D&D or perhaps it still happens in your games. From this and similar problems grew two rules in my gaming: 1) no evil player characters in heroic games, and 2) no major conflict or strife within the party unless it serves a greater storytelling purpose.
There was clearly a difference of opinion, in those situations, on the goals of the game. My goal was to have fun in a cooperative environment with a reasonable amount of conflict thrown in for excitement. Others viewed the game as a contest (DMs seeing a contest of wits in the granting of a wish) or competition (where the thief who has the most stuff wins). It is also true that some of these people had built up a mental picture and set of motivations, from which they were inflexible, for their character that were in conflict with other players having fun. When I read Gary Gygax describe adventures he ran or looked at Tomb of Horrors it sounded like what I think of as un-fun is some people's conception of the essence of the original Dungeons & Dragons game.
I'd like to see less complexity and I understand that we'll need to tone down the rules in order to get there. I prefer 4th edition to 1st edition but if I get my way we'll move a little closer to AD&D. However, there are some parts of the older, lighter rules experience to which I don't want to return.
Comment below if you've had similar or completely different experiences.
PS: I understand that the problems I'm describing come from human nature and not from the rules but game mechanics do matter.