Maybe you see a plant you have to collect in game or a rock wall that looks different. What items have you caught out of the corner of your eye that you realized was just your brain so focused on looking for things in a game that you saw it IRL and made you double take?
I used to imagine using a portal gun on various buildings to get to school.
They got you thinking in portals
I was going to comment this. I remember after playing a bunch of Portal, I saw a plain white wall up high and thought “that’s a good place to put a portal!”