|Scene from Futurama: Bender's Game|
1. Know The Rules
There is nothing more annoying than a player who doesn't know the rules of the game. The only exception to this rule is those players who are brand new to the game and are still learning how to play. However, if you have been playing for awhile now and still ask how to do relatively simple things, I think it's time you sit down and at least learn the basics.
2. Don't Be A Dick
While the occasional joke made in good taste is fine, constantly being disrespectful to both the GM and the other players is not alright. If I had to be perfectly honest, this trait is the most important to me. Since I'm older now and the amount of time that I get to roleplay has dwindled over the years, I'd rather play with people that I enjoy being around than dicks who enjoys ruining everyone's good time.
3. Be Creative And Describe What You're Doing
I don't know about the rest of you, but I HATE it when we are in combat and one of my players says, "I attack with my sword" and nothing else. That statement is just so boring and bland and makes it harder to reply with a interesting sounding effect since I have so little to work with. Instead, say something like, "I grip my sword tightly and swing at the opponent's head." With that, I have a lot more to build off of when I describe if you hit or miss.
4. Pay Attention To The Game
I really hate it when I've just finished describing the dungeon room they have just entered and one of the players looks up from their iPhone and asks, "I'm sorry, can you repeat that?" If you are going to pay more attention to that precious phone of yours, why are you playing in the first place? The only exception to this is if the person gets a text message or phone call that is really important and they have to take it. That I can understand. What I can't understand is someone who comes to a game to roleplay than spends the majority of the time texting their girlfriend or boyfriend and constantly asking, "Sorry, can you repeat that?" This is a real pet-peeve of mine.
5. Make Characters That Are Compatible With The Party/Campaign
While some inner-party conflict can be interesting and fun, it can get really annoy if its a constant thing that makes it hard for the players to actually work together. For example, if one person in the party is playing a paladin dedicated to the goddess of justice and valor, don't play the assassin who worships the god of anarchy and murder. Make a character that would for one reason or another realistically travel and go on adventures with the rest of the party. While some inner-party conflict might occur, you will still have enough reasons to stay with them and see that everyone succeeds at the end of the adventure.
While there are a few other traits that I'd probably add, these five are the ones that I feel are the most important to me. Also, before you all start to think that I'm biased here, I'm going to post a list about the traits I look for in GM's tomorrow. I've got to be fair, don't I?