Ask players about their favorite campaign and listen to what they describe. It is never the mechanics. It is the warlock's terrible decisions. The two-hour argument about a door. The NPC the DM invented as a joke who became the emotional center of the entire story. The system processed these events, but the table created them.
Rules are scaffolding
This is not an argument against rules — scaffolding matters; it holds the thing up while it is being built. But nobody photographs scaffolding. Editions will be debated forever, and the debates will always miss the point, because the variable that decides whether a campaign sings was never printed in any book. It is the particular chemistry of the people in the room.
The same module, run by the same DM, lands differently on a Tuesday than a Saturday. Mood is a mechanic. Trust is a mechanic. The friend who brings snacks is performing essential game design.
Choose the table first
New players obsess over system choice — which game, which edition, which rules. Veterans give different advice: find your people first. A mediocre system with the right table will outperform a perfect system with the wrong one every single time. The memories do not live in the rulebook. They live between the chairs.
Years from now, you will not remember your armor class. You will remember who was sitting next to you when the natural 20 landed.