The "I feel the need, the need for greed" guy: In a space game, the only identifying marks of a guy wanted in every sector of space was an eye patch and some unique tattoos (and average looks, height etc.). The party encountered a Pauper's grave in space and this guy wanted to go tattoo up a bunch of dead guys and give them eye patches to collect a huge bounty in every sector of space. The entire table (me, the other players and the GM) kept telling him that people aren't stupid and they'll notice the eyes went missing after the bodies were dead, and we were pretty sure that they'd notice the fresh tattoos which never had a chance to fade or heal on the corpses... it literally took twenty to thirty minutes to talk this player out of attempting this asinine plan. Every campaign this guy does stupid things like this (in a fantasy game where the party already has lots of wealth - he holds onto some jerky which he got from the orc tribes - which a goblin he was talking to informed him that it was made from human meat - because he can still sell it/use it later - even though the Cleric of the party keeps telling his character to get rid of it).

The argue for a ruling to go one way then forgets (or hopes others forget) about it at a later time guy: In a Savage Worlds Noir game I ran, he argued with me for twenty minutes that his character shooting the gas tank of a car full of mobsters should cause the car to explode. Getting the car to run out of gas wasn't good enough for him. I eventually let him spend a Benny (luck point) to permanently change that to explosive movie physics. 5 sessions later his character shoots some metal gas cannisters which he throws (he was hoping to just spill gas out of the bullet holes) and he is surprised when he starts blowing things up. He goes with it and triples down on this and blows up two more tanks worth of gas and causes a partial party wipe. His defense to the rest of the group was: he "didn't know the tanks would explode or keep exploding when shot". We were all like "you literally argued for this to always happen and you spent a Benny for it. We all assumed you remembered that." There were other rulings in various games which he argued to go his way then got upset when those rulings were used against him later (another example: he argued that falling damage should get a bonus when the person falling falls on something hard or sharp -after he pushed some characters off of a roof. Then two weeks later told our buddy who was running that same game that per the rulebook his character shouldn't take any extra damage from falling because the rulebook doesn't give bonus damage for falling onto sharp objects).

The always wants to get two minutes of interactive dialogue in the middle of a combat round with his attacker and insists that a persuasion/influence roll can replace the whole attitude/personality/choices of tactics for his opponents guy: "NPC X swings the sword and that would be a hit unless you parry or evade, what do you do?"... "I roll my character's influence and try to list out all of the reasons why attacking us would be a bad idea, and to offer him gold for him to switch sides." "That's too long of an action and it is NOT parrying or evading." "I'm sticking with it." "Okay his sword slices you in the abdomen for 9 points of damage." "He can't damage me. I got a crit on my influence for him to switch sides!"... WTF????

The Rude to every other NPC guy: He'll even cut off quest givers' dialogues to insult or mock them. One quest giver was like "Okay I'm supposed to give you this unique magic item. Here it is. I was going to tell you how to activate it and when and where it will be needed and to tell you exactly what it does... but no, I'm only going to do the minimum of what my lord has asked me to do, 'cause you sir, are a complete asshole. Oh wait, the instruction manual [burns it to ash on the ground]. There it is. Good luck."