Forbidden banished exiles. Especially in MMORPGs, I've found that the most common overall in-setting guild theme is "we don't belong in the society that this setting established." It's not just in MMORPGs, of course. It's often a crutch (or training wheels, if I'm being generous) for some roleplayers to participate by not participating. I'm not saying that a character (or a player for that matter) has to bend the knee to Lord So-And-So, but it's kind of hard to find plot excuses for the the forbidden banished exile to even be in the same picture, let alone get the quest to do the thing.
Plot armor dependents. Yes, it's quite likely that if I'm running the game and telling the story that I won't have the guards kill a player character on sight even if they do something exceptionally stupid just to see what happens, like stabbing a random citizen. Those kind of players don't tend to last long if their only contribution is "try to knock down the props just to see what happens on set."
People that directly lift an established character in well known fiction, often just changing the spelling, and often not even trying to resemble or act like that character. In an older MUD, I recall a "Frrodoh Bhaginz" that was a Half-Ogre hunter. Again, it didn't ruin the game, but it was annoying. I admit it can sometimes be a red flag warning, and a helpful one, if the lifted name is from chud fiction, like if they have "Rahl" in their name. It can show me what to expect, either in a tabletop group or in a MMORPG guild.
I think there's a notable distinction between Railroading and Pre-Game Prep Work / Playing a Pre-Written Module.
To some degree, players are at the table to play a particular game. If you're doing Ravenloft and your party decides to just fuck off to somewhere other than Barovia, then you're not really playing the game you said you were going to play. I don't know what players want their DM to do with the rest of the session when they say "We're getting on a magic boat and sailing to the Forgotten Realms instead". Why get angry when the set up for a story is "You're kidnapped and press ganged onto a pirate ship (which you will presumably eventually mutiny against)" if you said you were going to be playing a game of Pirates? Why whine about getting caught in the Death Star's tracker beam when you're literally running Star Wars: A New Hope, the TTRPG?
On the flip side, if the DM says you're at a fork in the road, but has absolutely no plan for what to do if the players take the left lane, that's poor planning. If the Dread Lord makes a threat that players don't take seriously, the DM needs some line between TPK and exposing the Big Bad as toothless. If the DM presents an open-ended puzzle or conflict and the players come up with a solution that doesn't quite seem to work, the DM needs a contingency for failure. Presenting players with options and then getting mad when they don't take the "right" choice is obnoxious. It also tends to fuel player-paralysis, as the players just kinda stop trying to make choices that they know won't matter.
There's always some gray area - a player escalating a conflict beyond what the DM anticipates (say, a Barbarian slugging the merchant for failing to offer reasonable prices, when the merchant is supposed to be giving them a plot-hook), or players getting "creative" in a way that circumvents a bunch of hazards or a major plot point in a way that significantly diminishes what the DM had planned for the day. And the better DMs will know how to roll with those unanticipated twists in a way that keeps the game moving while still being fun. Arguably, its these unexpected twists and impromptu moments of off-the-rails storytelling that make the game so much fun for everyone involved.
But by and large, the game should be about an interplay between storyteller and characters while still "staying on track". Otherwise, why have a DM at all? Just play a board game.
Personal experience may be shaping my opinion here, but the campaign that made me think of this was one where like 3 unrelated epic-level villains some form of magical compulsion to force Good-aligned characters to do quests on their behalf. It got to the point where I seriously felt like the best thing my character would do was throw himself off the nearest cliff because he was such a useful asset to the side of Evil.
That does suck, if its just being strong-armed. And, again, you do need some degree of contingency for when the players buck the system. So subverting the will of the villains by doing as-stated-but-not-as-intended executions of jobs could be fun. Dethroning the good king by getting him to implement a parliamentary democracy, rather than by stabbing him in the back. Burning down the orphanage after you've evacuated all the kids, and then moving them into a new luxury town home that you've purchased with your adventuring money. Whatever.
But simply having the GM announce "Your Paladin eats the baby because he has no choice" isn't particularly fun.
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Sometimes DMs are just assholes who like to piss in your punch bowl.
I do enjoy, as a DM, designing a puzzle with multiple different solutions, and then having the players try to 'solve' the puzzle on some completely separate idea that never occurred to me. Usually, if the players have a good idea for a solution, that doesn't directly conflict with important lore or plot, I'll just have it work, even if its not 'the solution'.