For me a lot of these points are quite specific and not deal breakers in themselves though an accumulation of them might be
I think I would walk from a game with advantage on flanking. I would probably also walk from magic item shops.
Like these. While I have no issues with either of them (I DMed magic item shops well exchanges) I can't see why advantage on flanking would get you so exercised that you would not want to play the game?
The only game I actually walked out on was where the DM fudged and wholesale decided what was occurring, thus ignoring player agency. Either of those things would make me walk.
This on the other hand is a very broad point & one made by several other people in slightly different ways. It is pretty much a deal breaker on its own. I want to play a game that involves partaking in a story telling exercise not being told someone else's story
I can't think of any one other thing that would stop me playing.
Excessive drinking and rude behaviour is a given as well. Unfortunately I had one player not return after being made uncomfortable by another player. I wish they would have spoken up, as we talked to the troublesome player after the session. I have learned since then that it is better to address those matters head on.
These are kind of outside the game & more relate to the general social situation but I would not want to play with people I did not get on with or in a smoky room etc.
Any game where the primary focus is on the numbers, where it's played as a wargame or tactical exercise above all other considerations. Nothing wrong with that if it's what everyone wants, but it's not for me. I'm in it for the story and the RP; the numbers are important, but--for me--they're in service to story/RP, not for their own sake.
Flip side of that, if a game is too railroady. (I give railroading more leeway than some, if it's a cool enough campaign, but there are still limits.)
I'd probably leave most games that are focused on PvP, too.
I on the other hand am playing a game which involves some RP. In the spectrum of RP games I play D&D is at the mechanical & combat heavy extreme (because it is the most robust & fun or at least 4e was) so I don't care about this.
Raliroading is an aspect of DMs telling their story as covered above. It's not popular.
PVP has its place & that place is one shot
Paranoia games
I have never and will never walk out of a game. I don't know how I would feel if I ever saw someone else do it. Now, not coming back after the first session? There are a few things that will make me do that:
- The DM can't let go of their story. D&D is, primarily, a story about the players. The DM provides the conflict, the PC's provide the protagonists and conflict resolution. If a DM tries to mold these in such a way to fit their vision, you're on rails. Pass.
- The DM won't let me speak. I LOVE a descriptive DM. But there have been occasions where the describing never ends. We sit there for five minutes of description when we are itching to get to action. Don't describe the stucco walls, the dark brass fixings and the antique globe on the dark wooden desk unless it's important. Say it's decorated in Spanish Colonial and let's get moving. Pass.
- Heavy house-rules. This is a big red warning sign pointing me back to #1. They've got a "vision" for how this is supposed to turn out, and they are changing the rules to enforce it. Solid pass. In fact, I probably will have "something" come up to prevent my attendance.
Common themes. I am not in theory averse to house rules though I pretty much never use them myself. (Though I think people who use them tend to forget they made the house rule so I expect I do too - things like summon natures ally summoning 1-2 creatures of your choice not 8 of the DM's)
[*]DM incapable of thinking outside the rules. This may sound like a conflict with #3, but it's not. Sometimes a DM needs to rule a certain way contrary to RAW, or even RAI, based on common sense and context. Game rules are not the physics of the game world; they are a rough model for adjudicating how those physics result. I am not playing in a game where stupid and/or unbelievable things happen because of strict adherence to RAW. Pass.
Interesting. For me this is one of those incremental rules that I can live with is small quantities.
One friend described a DM we play with of being unable to let go of the rules even when it would lead to a better game. Mind you this same friend gets agitated by this same DM making narrative based rulings, ignoring the rules, when he feels it will enrich the game.
I like how 5e has empowered DMs to do this - I used to get caught up in RAW bizarreness in 3e.
The important part IMO is being careful with precedent. Sometimes you have to flag a special case so as not to set precedent but mostly you have to be consistent. hmm side track.