With FPS, I have to keep reloading. I always feel like if I don't, then I will run out of ammo in the middle of combat and die because I had to reload.
In RPG's, I have to keep my health full (or at least close to it). This applies to everyone in the party.
In fighting games, if I win a match, I usually do my characters taunt (which is a bad thing for online play, but it's a habit).
In just about any game, I have to start off playing as a female character. I usually don't like male characters, and in games where I create my own character, I always make females, like in Dark Souls and Fallout.
Yes, I reload after every kill. Whether it's a NPC, or another player I always reload out of habit. I'm not sure which game in particular started this habit though, probably a game where a full clip would be needed to kill an enemy.