I've definitely experienced this before. The only time I've ever worried about this sensation was after playing a lot of Burnout. I caught myself automatically determining the shortest path on roads, around curves, and through oncoming traffic. Thank goodness I wasn't the one driving, though realistically if I were driving I don't think I would have driven in oncoming traffic, but I might have taken the most efficient path in my current lane.
Most of the time, however, I just use gaming experiences or constructs as metaphors in my thinking and that's not so much changing how I view reality, but more how I explain it to myself.
I too have found myself in the past thinking about portal shortcuts though that was simply due to me not wanting to walk around campus. I've determined that the exterior walls of the buildings (made of brick) probably wouldn't work very well but the interior walls would be perfect for portals.
I also found myself thinking in Shakespearean English (even in iambic pentameter) shortly after I finished reading King Lear.
On a side note:
What's up with the whole "white wall" preoccupation with portals that everyone who mentioned portals in this thread seems to have? Have you guys not played Portal 1? Have you honestly never shot portals on the greenish yellow walls of the hallways with the hatch doors in Portal 2 for the fun of it? White, seriously? The color doesn't matter at all!
Ranting:
Portals can be shot on non-metallic surfaces that are flat and have enough surface area to support a roughly person sized portal. The notable exception involves conversion gel composed of lunar regolith and that only happens to be white (the same restrictions of flatness and area apply). Compatible surfaces commonly available in both Portal and Portal 2 are made of concrete, drywall, or covered in lunar soil.
Nerd Rage:
Honestly, associating portals with specifically white walls? Did we even obsessively play the same game, it's sequel, and the original prototype* by the development team in anticipation of the game's release? I am disappoint.
*Narbacular Drop if you're curious, there's no portal gun but still portals abound.
Okay this port is hella long but I found this hilarious:
First read it as "fell lesbians" but I imagine Evil Lebanese Psionicists to be far more frightening.