Here is a list of elemental mistakes that a GM can make. The order is not very important, although point 1 is more important than point 10. Have fun reading.

10. You have a favourite NPC.
Check here for more details. Basically, the more your NPC plays, the less your players play. You want your players to have fun too… I don’t think there is much more to explain. 95% times, leading a character, besides being a GM is wrong.

9. You have a story prepared, that you really don’t want to change.
This is never a good sign, even if the story you want to tell is really great. The first thing you (should) learn as a GM is that players act unexpectedly. Therefore, they will always change the story, at least its details. Keep in mind that, after all, it is about the characters, not a supernatural force manipulating their fate.

8. You kill a character at least once every two sessions.
Yes, players rarely like to die. See this post and read comments for more details. Killing a PC, although it can be fun, players don’t like being killed. Especially if they do not deserve it. Of course, there are some systems/settings in which players die very often. But I don’t believe that they enjoy dieing, even in those engines.

7. You believe that failures make your players stronger.
In other words, if they keep losing all the fights, they might eventually find a way to defeat those enemies. It doesn’t work. Your players may think it was a good idea when they had lost once and than, in another epic battle defeated those damn villain. Such strategies are sometimes good for the whole story. If the players lost twice, it is still quite okay. If they keep losing 3 or more times, one day they just won’t come to play with you. Sad, but true. I know that, once you have made a cool villain, you don’t want him to die. But live is brutal, eventually he has to.

6. You completely don’t care about crunch.
Well, this is quite a complicated issue. Although I always thought that the mechanics are just an addition to storytelling, they really are important. Or, in other words, you can’t ignore them completely. No matter, if they are your house rules, d20, whatever. Why are the mechanics so important? Because they add the element of chance to the game. Nothing is 100% sure to happen. Moreover, rules are for the players, so they know what skills to develop, when they characters get stronger etc. You can’t play only with storytelling, fluff, because it leaves nothing to the chance, and everything depends on GM’s decision.

5. You completely don’t care about fluff.
That’s also wrong. If all the crunch is a brain of RPG, descriptions are its heart. They create an atmosphere, ambiance of the game, things which are the most important part of RPG. Without descriptions, setting and so on, RPG would be like mathematics, not entertainment.

4. You don’t prepare your adventures at all.
Although some may not agree, I believe that the more time you spend on preparing an adventure, the better it will be. You need time to polish up all the details, NPCs, scenes. If you rely only on your improvisations skills, even if you are really good, there are times when you just shouldn’t improvise. You can’t invent as many details in the moment of speaking, as you can while doing prep.
However, it is also wrong if…

3. You don’t improvise at all.
This one is connected with point 9. Players need to feel, that they have some freedom when playing. That they can go everywhere and do everything. If they do, they’d love your sessions. You can prepare a lot, but if you don’t improvise, players may walk into a room, you didn’t prepare. Or kill a guy they were supposed to talk with. Don’t save a princess, but burn a castle. In order to make great adventures, you need to combine both things: preparation and improvisation.

2. You think you can’t get better as a GM.
This one really sucks. Nobody is perfect, no GM is perfect. Really. You have to keep in mind, that you can always get better, your campaigns may be better, your descriptions can be better, you can use rules even more efficiently. When I prepare a new campaign, I always think like: Yes, this one is going to be sooo much better than the last one. I always try to make my adventures better. You should do it too. Read RpgThoughts, read other RPG blogs or boards. Ask your players for feedback. If you’ve mastered one system, try another one, maybe you’ll have even more fun playing it. Always struggle to be better…

1. You don’t care if your players are having fun.
This one is the elemental rule of GMing. You have to care about your players. Ensure they are having a good time. This doesn’t mean you should bring beers and chips on every session. But in all the things connected with RPG - you are the boss. If something goes well - it is your success. If something goes wrong - it’s your fault. Whether your players are having fun or not it is up to you. And you want them to have fun, otherwise they are not going to play with you.

I just wanted to say, that I hope noone feel offended by the title. I just wanted it to sound oh-so-exciting

Are you suffering any of this GMing illnesses?