Perfectionism - If a game has level/mission rankings and/or a list of optional or hidden objectives, I keep replaying to try to get the highest rank and clear all the objectives before i move onto the next mission, on my first playthrough. If there are significant roadblocks in the way of this (usually time or poor/tedious design), my enthusiasm for the game gets completely deflated and I stop playing. Thing is, these objectives or ranks are usually designed for you to come back with upgrades or tools you get later in the game, or after you have beaten the game, not your first time through like I keep trying to do. What's the definition of insanity again?
Consumerism - I only finish games I bought. Have never finished any of the many games I have either emulated or torrented, no matter how much I was enjoying them. Money has a way of prioritizing things.
Stealthism - Doesn't matter the genre or if the other options are more fun, better designed or more interesting. If the option to sneak is there, I will take it always.
Perfectionism 2: Stealthism - I always try to ghost on my first playthrough. If I get spotted, I reload. Thief levels take me hours.
Pefectionism 3: Well laid plans - If a scenario doesn't go how I envision it, like a stealth sequence or perfect ambush, I will keep reloading until it does. Games that involve a lot of setting things up and precise timing windows (e.g. Hitman, MGSV, Commandos 2) especially. And I'm real particular too. Like in STALKER: CoP, the quest where you have to get the artifact from the dredge station and are confronted by 3 stalkers: I had to kill them in a certain way, from a certain position, certain weapons, and do it without getting hit, and I reloaded at least times until I pulled it off.
Have Sniper Rifle, Will Default - Prioritize sniping over any other type of shooting.
One Shot, One Kill - Almost always prefer single shot or semi automatic fire, even when full auto is available on the same gun or is the cooler/better option. I do better in MP shooters with semi auto weapons, too.