Lawful good and neutrality and chaotic neutral and neutral evil and how silly it was that you said a totally self-absorbed man was neutral. He might live like an animal, but an animal's neutral precisely because it can't know better. And it's so different from a druid's neutrality to maintain the balance. Should a neutral person just balance out, or avoid all extremes? Someone defended it as a useful short hand for NPCs. I observed that you took philosophical conudruums that people have broken their hearts over for millennia, misunderstand half of them, boil them down to game mechanics, and then hand them over to sophomoric games (some of whom, indeed, have the excuse of being sophomores), and the result will be ugly. (As one panelist observed, boiling most things down to game mechanics is ugly, but I think alignment's something special among them.)
the virtues and vices of all the systems. All of which have fans. The gateway drug, and the way anyone would probably know how to play it. The extreme flexibility.
A horror story of a game where they had literally no encounters going through the forest, they arrive at the city, the enemies arrive to attack -- and the DM ends the session before they actually get to fight. Or the DM recounting the time the character had used Tensor's floating disk to get over the runes that would have summoned the zombies and got them all in a single blast. They got bonus XPs.
Authors can characterize very well. What they are not good at is working together as PCs. Many difference. A writer's plotting is a DM's railroading.