In space battle simulators, for instance while dodging asteroids, I always tend to lean into the desired direction. Leaning back while pulling up, leaning forward while diving…
In FPS games, when there is something hidden behind a corner, I tend to move my head first to look around it, instead of using the game controls.
Answering random NPC chatter and story dialogue in-character, as if I was roleplaying the game hero.
When being asked a question by Alyx in HL2, I sometimes “nodded” or “shook head” by moving the mouse.
I’m also an explorer - going everywhere, trying to do everything, gather every piece of loot, hit every button, crush every enemy… visit every place in a game. Even though in real life, it wouldn’t make any sense.
Reloading after almost every single shot, quicksaving after every kill or every difficult stage of level navigation. Quickloading after every unnecessary loss of live energy, hitpoints, armor power, whatever.
Always trying to protect as many npcs from getting killed as possible. Quickloading whenever an npc unnecessarily dies.
Trying to use stealth even if it has no useful effect in the game.
Always using the weapons my current enemies are using as well. For the benefit of ammo.
Always experimenting until I find the most clever way to solve a dangerous situation in a game.