See, but the Bad DM knows that the players will not like railroading, so, he covers his railroading by saying that the guard is a member of the temple guard. See, you're thinking that the Bad DM is stupid. He or she most certainly is not. See, the Bad DM doesn't think they are a Bad DM. They think they are a Good DM. And they know what Good DM's will do, because they see advice like this. So, again, from the player's POV, a lot of times Good and Bad look exactly the same.
No. Bad DMs aren't sitting there steepling their fingers and laughing evilly and trying to pretend they're good DMs. They're telling a specific story and don't want player interference in it. Plus, as I said, there's a pattern of behavior. Players
will find out that the GM is railroading them. And no, it's not because the Bad DM is stupid and it's not because they're evil. It's because the Bad DM has a story to tell and the players are along for the ride. They don't care about the advice because that advice gets in the way of telling their story.
Anecdote time: Years and years ago--I mean, back in the 90s--someone in my then-group wanted to run a game of Changeling: the Dreaming. Now, this person had been in my game and basically tried to sabotage it[1], but at the time my ability to confront people was very poor so I never was able to deal with it properly. But Red Flag #1, as this indicated his pattern of behavior.
We were told to make characters who were students, staff, or faculty at a particular high school. That was our only character guideline. I wrote a character who was a substitute teacher as a way to pay the bills until she made it as a novelist. She liked being a substitute because it let her teach and also gave her plenty of free time to write.
He decided that the game involved sending us teachers on a quest to prove we were worthy of tenure, thus completely ignoring the fact that my character
didn't want to be a full-time teacher. I mentioned that and he said no, I wanted tenure so I was going on the quest. Red Flag #2. (I can't remember why the students were along for the ride, but it was for a reason that ignored whatever was in their backgrounds as well.) I only went on the quest because, as I said, I was bad at confrontations at the time.
So we went to the Dreaming or whatever it's called in C:tD, found a village, and were quickly plonked down into a retelling of Snow White. Not what I was hoping for, and not actually interesting, but I can deal.
One of the other players was playing a redcap student. Dunno if you've ever played C:tD, but redcaps can
eat. Like, anything and everything. They are always hungry and can't get full. That's a large part of their shtick. Anyway, at one point the PC said a curse word and, because this is the Dreaming, got hit in the face with a pie as punishment. The player quickly realized that cursing equals free food and started swearing up a storm. The GM realized what the player was doing and told him that his character was full and didn't want anymore pies. This is completely antithetical to the concept behind redcaps.
This player was
very good at confrontation and
did not want the GM to tell him what his character was thinking. Cue a huge argument and the end of the game.
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I ran a Ravenloft game--not using D&D but a different system; can't remember which one (I've run Ravenloft in a
lot of non-D&D systems). I asked this person repeatedly if they were OK with horror and they said yes. I asked the entire group after each session for feedback and complaints since I was new to GMing and very unsure of myself, and I and got crickets from him. I asked him
specifically if there was anything he wanted to change and he said no. After a couple of sessions, he began to refuse to engage with the horror and played their character as a happy shiny fun person and made snide comments about the plot, descriptions, and everything else, thus completely ruining the mood. When I asked if he could tone it down, they said they didn't want to play a horror game and played their character that way to make it not be horror. Unfortunately, he was my BFFs housemate/landlord and it was his house, so I couldn't do much about getting him to leave.