I find it interesting that a lot of people don't realize just how different D&D can be from table to table. I will use my own campaign to illustrate this.
New Model Colony is a campaign setting of my design, intended to be run using the West Marches model and operated as an Open Table, and informed by Ray Winninger's Dungeoncraft articles on worldbuilding. (The key seven rules summarized below.)
- The First Rule of Dungeoncraft: Never force yourself to create more than you must.
- The Second Rule of Dungeoncraft: Whenever you design a major piece of the campaign world, always devise at least one secret related to that piece.
- The Third Rule of Dungeoncraft: Whenever you have no idea what the probability of success should be for a particular situation, consider it 50%.
- The Fourth Rule of Dungeoncraft: Always challenge both the players and their characters.
- The Fifth Rule of Dungeoncraft: What's done is done.
- The Sixth Rule of Dungeoncraft: Simple, easily identifiable characteristics are the best tools for portraying NPCs.
- The Seventh Rule of Dungeoncraft: Running a good campaign is about building a world, not building a story.
And, following good practices that get desired results as explained here I cut away things that take away from speedy play at the table, and then more from the pre-Tolkien pulp fantasy theme I'm after.
- Roll 3d6 in pre-3rd Edition order: STR, INT, WIS, DEX, CON, CHA. If none of the first four are 9+, raise STR to 9; you're playing a Fighter.
- Class Options: Cleric, Fighter, Magic-User, Thief.
- Race Options (for when using AD&D): Man only. (Note: I use "Man" and not "Human" in my fantasy gaming.)
- Power Options (spells, et. al.): See DM.
- Vitals: Roll randomly for HP, minimum 1 HP/die.
- Gear: Firearms are available; see DM for details.
- Alignment: Yes.
- Table Rules: No adventuring (etc.) in town; town is safe. Expanded player-character options must be won in-game; they are another form of treasure. XP only for treasure returned to town.
I don't allow unfettered selection of spells, and religion is monotheistic (which influences Clerics). I emphasize exploration, location and recovery of treasure. Getting to Name Level matters because it pushes back the frontier by making a new town to operate from. Finding the best treasure means solving the setting's mysteries, and that lore is only found where the dungeons are. Learning new spells requires mastering in play the symbolism behind the spell's intended effect. (No mindless play at my table.) And so on. Rules-As-Written is NOT A THING HERE.
This is so different from what you see on Critical Role, or MissClicks, or Acquisitions Unlimited, or what the Gaming Dens demands. Yet I am using the same D&D materials as many others, and to onlookers it will seem no different; only if you play do you grok the differences, because you are only in a position to comprehend it properly when playing.
The rules are not the game. The table is the game. The observer cannot grok what is seen. Only the participant can.