I think "T Shift" in my head before I speak after 1000 hours with a few people on a Minecraft server. T to open chat and shift for capital letter.

Also its not really a habit because I try to do it but I imagine quick time events. :D

I constantly reload when capping points.

When considering whether I should do something risky I wonder when my last save was.IRL.
Not exactly a good habit.

Reet72:
When considering whether I should do something risky I wonder when my last save was.IRL.
Not exactly a good habit.

this, Im getting a new gaming PC and found myself thinking "putting X part in looks tricky, I'd better quick save before doing that"

After some TF2 I constantly find myself using heavy or medic's accent or yelling out demoman's kaboom taunt for no reason

Sometimes when I'm standing still i start doing the animatons protagonists do in games when you leave them alone :P.

I've developed an IRL ignore list. It works, too.

Well i do find my self looking for the "hit B to kill" prompt more and more these days.

I don't have the physical prowess to do most of the stuff people do in games...

But for a while I could not stop thinking in portals in the real world, which makes me sad such a technology doesn't exists.

I can't sit on benches anymore without folding my hands together and bowing my head forward. Some of my friends have even called me out on it because I tend to always wear a hoodie xD

Just like in rpgs, I make sure I have everything I could ever possibly need before going anywhere.
Also the Professor Layton puzzle theme plays in my head whenever I try to think.

I take animations and body language off characters. I never crossed my arms before I played Mass Effect 2, now I do it all the time. Same with putting one hand on my hip or sitting in the seiza position from Fate/Stay Night. My running movements generally take from whatever game I've just been playing. Et cetera.

As a habit of being brought up on Tony Hawk games, I used to look at everything and decide if it would be grindable and what sort of skateboard tricks you could do off it.
That's kind of wearing off now, to be replaced by the Assassin's Creed sensation of deciding of stuff is climbable. The older the building, the better.

Daaaah Whoosh:
When I walk through a crowd, I turn my shoulders and sometimes put my hands on people's chests, just like Altair. Thankfully, it's only a short-term effect of Assassin's Creed playing.

So I'm not the only one who does that but I usually do it while wearing my hoodie and listening to the Assassin's Creed theme song. Oh I also take time going down the stairs and explore my environment listening to my thoughts as if I am in Heavy Rain.

Mainly just paraphrasing, also occasionally I go so far as to actually quote. :D

After playing as a fully Renegade Shepard in all three Mass Effect games in multiple playthroughs, I have found myself to be more assertive and "alpha male-ish" in conversations. I wouldn't be surprised if, while I'm having a conversation with someone I don't like, I punched them in the face as they are talking. Also, for their own safety, I tend to stay away from reporters.

I steal everything i can, most of the time it`s useless stuff and i`m still glad the police didn`t caught me after one of my GTA sessions.
I also tend to reload after almost every single shot.

I kept trying to turn Detective Mode from Arkham Aslyum on in real life, it didn't work.

Also doing the Dead Rising at stores, seeing what items around every store I go to could be used as a weapon

When I used to play a lot of FFXI, I would find myself trying to type /map when I woke up in the morning. Looking at the map had become almost a nervous tic for me.

Back in November of last year when Skyrim came out, I was playing it a bit too much. Around that time, I cut myself while shaving and decided it was best to reload a previous save. I stood there for about 15 seconds before the reality of the situation dawned on me.

After my birthday, someone asked me how old I was. I almost told them Level 18. I had to sit there for a few seconds to think on what the actual term was.

Also, sometimes I check rooftops for snipers. That's always interesting.

I pretend I'm in Persona at school, for the sake of not being bored out of my mind. And it helps with my social skills.

Well I use a lot of gaming quotes...a huge amount actually.

And I check roofs and buildings for enemies.
I look at people thinking they might be a templar.
I move through crowds like an assassin.
I look at Items I can use as weapons like Dead Rising.

That's most from now, I'm sure I have more but I forgot. :P

Well...when I have to go through tight crowds, I do Altair's thing where he sort of grabs their shoulder and pulls himself forward gently and swims through. But this isn't unconscious. I tried it the first time for fun, but I do it now because it really works.

Oh and when I have to take my dogs for a walk I refer to it as dual wielding (I have two dogs).

After playing AssCreed II, I've started knocking before opening any door. Obscure reference, because it only happens before your family gets killed (IIRC), but it's true.

Also, I often wear suits (Hitman).
I constantly move the furniture in my house (Animal Crossing).
I whistle to get peoples' attention (Pikmin).
And I never buy anything because I'm just gonna get a better version in the next dungeon (Any RPG).

When I am driving I drive on the sidewalks and trying to hit as many people as possible.

Daaaah Whoosh:
When I walk through a crowd, I turn my shoulders and sometimes put my hands on people's chests, just like Altair. Thankfully, it's only a short-term effect of Assassin's Creed playing.

Ah! I neglected to mention that. Ever since playing AC 1 back in '07 I've had the same tendency to grab peoples' shoulders if walking passed them in a crowd.

Richardplex:
I take animations and body language off characters. I never crossed my arms before I played Mass Effect 2, now I do it all the time. Same with putting one hand on my hip or sitting in the seiza position from Fate/Stay Night. My running movements generally take from whatever game I've just been playing. Et cetera.

This is the biggest one for me. The hip-pop/lean back with the arms crossed.

I find myself doing this all the time now if I'm replying to someone in a serious conversation.

If I play Assassin's Creed for a bit I'll start sprinting with my hands toward my feet like in the game heh.