I'm really obsessive about hoarding ammo in FPS games. If possible I'd go through the whole game with fists only even if it made me take five times as long to complete the games. I also have to complete the automap in games that have them and I have to talk to every NPC multiple times and check every flower pot for bonus stuff, regardless of how much I need it. I also feel compelled to pick up all bonuses that enemies drop regardless of whether I actually need them. Even in the original Zelda when you're limited to 255 rupees, I still freak out if I fail to pick up a coin.