GM Advice: 6 Common GMing Mistakes

No GM is perfect. Everyone makes mistakes from time to time. Some mistakes, however, seem to crop up again and again.

By William McAusland (Outland Arts)
By William McAusland (Outland Arts)


Over the past 30 years I’ve seen GMs make loads of mistakes. Sadly over the last 30 years I’ve also made all the same mistakes myself. I’m not talking about rules-based mistakes; that would be a crushingly boring subject. Rather, I’m talking about even more basic errors that every GM is guilty of from time to time.

I’ve previously posted about the 5 characteristics of terrible GMs and the 8 characteristics of great GMs, but in my mind there are six basic mistakes an GM can make:

  1. Inappropriate Rewards: Sometimes a GM gives out too much – or too little – treasure. Both extremes are bad. If the PCs don’t get enough treasure, XP or whatever they’ll grow resentful and bored at their lack of success. Similarly, if they get too much, the campaign spirals out of control pretty quickly as they develop capabilities far beyond what their level assumes.
  2. Inappropriate Challenges: Every party occasionally gets into a fight they can’t win – or one in which one of their number will likely die. Such fights are fine on occasion – as long as they are not a total surprise – but having them every session is a bad idea. I once had a GM who didn’t seem to think he’d had a good session unless someone had died. We got to the third adventure in one of Paizo’s adventure paths with only one original member of the group left. In those three modules, the party had suffered 16 deaths! Needless to say, we didn’t finish that campaign.
  3. Playing Favourites: This is a classic GM mistake. Some GMs do it subconsciously – perhaps they find a player’s character more interesting than the others – while others are more aware of their actions. While the extra attention, cool story devices, treasure and so on are great for the affected player it is less great for the rest of the group.
  4. Not Keeping Control: A GM not in control of the table is doing a disservice to the players. A lack of control could manifest itself in constant rules arguments or could simply result in crushingly slow game play because players are checking their phones, talking about non-game related stuff and so on. While a GM shouldn’t run his game as some kind of totalitarian police state, he should be in charge of proceedings.
  5. Not Preparing: As a GM, turning up unprepared is a disaster. My pet peeve is a GM who turns up unprepared, loudly announces the fact and then runs a very slow, boring session as he tries to read the module on the fly.
  6. Trying To Win: I once had a GM who constantly seemed to be trying to win the game. I think he fundamentally misunderstood the GM’s role. A GM wins, when everyone has fun. He doesn’t win when his monsters loot the crushed and broken bodies of the PCs or the players get so frustrated they leave the dungeon (or the campaign)!

Help Fellow GMs

Have you made some of those mistakes yourself? Have you seen GMs make any other common mistakes? If you have, share them in the comments below and help your fellow GMs game better.


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Creighton is the publisher at Raging Swan Press and the designer of the award winning adventure Madness at Gardmore Abbey. He has designed many critically acclaimed modules such as Retribution and Shadowed Keep on the Borderlands and worked with Wizards of the Coast, Paizo, Expeditious Retreat Press, Rite Publishing and Kobold Press.

24 thoughts on “GM Advice: 6 Common GMing Mistakes”

  1. Challenge/Reward is a hard balance to strike, especially without a lot of familiarity with the system in question, as you point out even modules have issues.

    Which adventure path? I’ve run a few and have my suspicions but would like to know…

    1. Best thing I’ve found is to give out sillier magic items. Like, maybe you get a frying pan that converts an enemy into a cooked meal on the killing blow. Or, maybe you have a plain looking sword that can expend a single charge every short rest for a boost to accuracy or damage. Then hand those out instead of a +1 sword or something. It keeps their power in check while adding fun magical elements and minor power spikes. There’s quite a few good fan made resources for this kind of stuff.

  2. I wanted to throw out my support, I really love your articles about being GM. I think #3,4 in this article are really good points, and often over looked. If a game has lots of PC arguments and inter party conflict the GM is not exerting enough control over the situation.

    1. PC arguments and inter-party conflict are not an issue with the GM not controlling the game – and if everyone is enjoying the game there’s nothing wrong with it.

      *Player* arguments, on the other hand, are a serious issue and likely to destroy the game and certainly can represent the GM losing control.

  3. #4 is a huge problem in every game I’ve ever been in, whether I’m the GM or not. Players just don’t seem to care anymore. They want to talk about their week with other players, whether they want to listen or not, and technology is so rampant that everyone’s always on their phone texting or playing games. A GM is supposed to be respected, and regardless of the age of the players (I game with people as young as 20 and as old as 55), I’ve seen no difference in this.

    1. Technology is a huge challenge today. Given so many of us use gaming apps it’s very hard to get away from tablets and mobiles at the table. I did ban laptops a couple of years ago, and no one seemed to mind. I don’t think I’d get away banning tablets (or phones) at the table.

      1. Rule at my table is only apps related to the game. Book pdfs, character sheets, dice rollers are ok. Twitter, reddit, facebook, candy crush (even if you are looking at forums for the game)
        If the tablet/phone is a convienint way to store a character sheet and the 5 books you need for the game i’m in favor of it. This relies on some trust in your players, and i do have to give out the occasional reminder (once I had to threaten XP loss). As a GM, you should be able to tell the diference between “its almost my turn, how do the graple rules work again?” and “look at what this politician said!”

  4. One of my buggest pet peeves with a gm is that a player is only able to perform a certain act if its in the book. The book is not going to contain every physical act known to man, that’s why a generic skill stat is created to offer a player a better chance to role play their character. Otherwise it might as well be a video game with established set bounds that can’t be broken.

  5. When the GM uses a published adventure and doesn’t adjust the adventure to fit the party they are running it for. Nothing is more frustrating than discovering a bunch of divine scrolls in a party with no divine casters, or a magic bow in a party that has no proficiency with the weapon.

    By the same token, GMs who don’t incorporate the elements of their player’s character back stories into their campaigns earn my ire.

    1. I’d suggest – depending on the mechanical depth of the system you are playing – very few people are lucky enough to be able to do this. I’m a pretty good GM (I think) but I couldn’t run a Pathfinder session in 30 seconds. Sure I could come up with an idea, but the I’d come unstuck with the mechanical aspects of the game.

  6. This is a great list of common mistakes, and a helpful checklist of bad traits to keep in mind and make sure not to fall afoul of. I’ve been working on a series of short articles covering the same general topic for a gaming website I write for, and it was reassuring to see how closely my ideas of what were the essential problems for struggling GMs lined up with yours.
    I’d based mine on the “seven deadly sins” of gamemastering and was equating each with one of the traditional sins, such as pride, envy, wrath and so forth. I’ve gotten through those first three, and it strikes me that each one of my points is echoed by one of your 6 common mistakes. I see a close link between what I wrote on pride and your comments on “trying to win,” between envy and “playing favorites,” and between wrath and “inappropriate challenges.” I’d started writing my upcoming article on sloth and it’s a clear ringer for your “not preparing.” Avarice should also line up nicely with “inappropriate rewards.”
    It strikes me that these must be pretty universal characteristics if we are coming to them independently. It’s nice to see more discussion of what separates good GMing from bad and to find that others recognize the same characteristics. Great list.

      1. It’s posted over at a gaming website I write for, (We translate that as “school of games.”) Here is the direct address for it:
        This is the third installment in my series, specifically on Wrath. I’ve also done Pride and Envy (which it has links to), as I’m taking them in the traditional order (I’m a medievalist by profession – meaning I teach medieval literature, not that I live in the middle ages or something). The conceit is probably a bit too arcane, but I’m sort of committed to it by now, and it does force me to think about how these GMing issues are related to more widespread and universal human problems. Please take a look and let me know what you think!

  7. As regards number one, it’s worth mentioning that not all rewards need to be treasure. Progression and rewards can be treasure, but they can also come in the form of “feature” progression (XP or other character competencies or abilities) and narrative progression. Blowing up the Death Star didn’t net anyone piles of treasure, but it was a wonderful dramatic/ narrative reward for the participants (and audience…).

    As always, simply communicating and knowing your group’s tastes can do a lot of the GM’s heavy lifting here.

  8. The list reminds me of my very first time GMing. I had a “great” idea for a drow-based campaign (yeah, I was young) and got a couple friends excited about it. I spent the next week lovingly daydreaming about the drow city, filling a notebook with details and information. I had overlooked coming up with something for my players to actually /do/.

    The first session came, I said, “okay, so what do you want to do?” and one player wanted to go kill a house matron, the other wanted to piece together some bones to make a skeleton horse(!) to ride around. Aaaand, a few minutes later we closed books and went back to a video game.

    GMs, be prepared, and be prepared in a playable way!

  9. One of the tricks I’ve learned to use over the years to combat some of these problems is rewarding scouting and stealth. I let the players scout ahead in a dungeon, and observe not only obstacles, but potential rewards. For instance, they might spy out a chamber that contains several monsters, but, while spying, they also get a glimpse of the treasure that they’ll gain should they overcome those monsters. This gives them a chance to plan ahead, measure risk vs reward, and maximizes their agency. Then, if they do get overwhelmed, it’s a direct result of their actions rather than a bad GM.

  10. For most of these the reason that they ‘happen’ is mainly due to inexperience…I was even guilty of the first one when I first started being a DM…as I gained more experience I started using common sense and thought about how much treasure would be collected by various monsters and the like and I feel I’ve gotten to a decent level of rewards for my PC’s..
    It’s usually every DM’s or GM’s desire to make a mega challenge for his PC’s…again, mainly due to inexperience but in this case it could also be due to ego..’Let’s see now, I have five PC’s all 2nd level, I’m going to throw in three black dragons, of course they are going to get mauled but hey, it’s MY scenario, I can do what I want.”…. To me I try and make it challenging in the mental aspect because you would think that it’s a PC’s ‘job’ to not get killed…it’s not necessarily the DM’s job to kill the PC’s or party.
    I’ve never really done this, I believe it’s more of a player thing, they have their favorite characters that they want to play and so they level out at 20th level or so and then have to retire…I’ve been playing a character now going on thirty years and what I’ve done is when ever he has leveled up, I make another character sheet out that way, if I go to another party and they need a certain level character, I just pull out the sheet for my character when he was that level. I then show the DM the sheet and if he disallows certain items I write them down on another piece of paper and then erase them on the character sheet…I also have a very extensive back history for him as well, it’s ever evolving:)..
    This has happened to me a couple of times, even with my experience, so what I’ve done is lay out a few ground rules and of course the dreaded house rules 🙂 and for the occasional ‘hiccup’ I haven’t had any real problems with this..I think out of the six reasons on here this is the #1 problem for any DM..
    This one is possibly for the new DM and again it also affected me as well..when I first started being a DM, I prepared for what I THOUGHT, I needed to prepare for, but as I dm’d I noticed that the PC’s would do things or go places that I didn’t plan and prepare for them to do or see so to speak so I would write things down and then after every session I would have kind of a Q&A session and try and incorporate them into my future sessions and I’ve come to find out that my PC’s actually like that, that I listen to them and in return I fix #’s 3 and 4.. Or at least I hope so:)…
    This one is kinda hard, I don’t ever remember doing this even when I first started out being a DM….I understood the fact that there are no traditional winners or losers in this type of game and like Creighton has mentioned if the scenario is a success then everyone has won, if the scenario has fallen flat then everyone has lost in which case the DM needs more experience and needs to remake his/ her scenario….

    1. I love the idea of keeping different versions of the same character to use in different adventures and campaigns. I’m baffled as to why I haven’t come up with that particular plan myself. And it’s so easy to do with computers these days. I keep copies of all the PCs in my campaign in Evernote in case something happens to someone’s sheet. Its easy to forward or print and play if the worst happens!

      Thanks for the idea.

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