Reminds me of the time I swapped cars with my wife (usually because it needs something done that she basically won't do, like take it to the car wash or for an oil change) and when I got out of work, I stood in the parking lot for 5 minutes dumbfounded that my car was 'stolen'. As I started walking back to the building to call the police/ get help, it finally dawned on me that I took the other car to work and was staring at it almost the whole time.
...though my most mortifying moment was when I was 18 (1998) and my parents let me use their Infinity one day as long as I took it for gas. Their car was just a bit of an upgrade over my '89 Ford Probe that had been through 4 accidents with my older brother and had about 16 things wrong with it.
I got to the gas station and the attendant asked me to open the tank. I said "oh, it's right there" and pointed out my window to the car's gas tank. He goes, "I know, but you need to unlock it." I look at the lid, don't see a keyhole and basically look about as intelligent as a sack full or doorknobs as I ask him, "what do you mean? How do you unlock it?" He starts smiling and tells me there's usually a "switch" in the car. Now I start looking for a literal switch (like a light switch) in panicked fashion and can't find it...
...I ended up asking for a minute or two as I scrounged up 50 cents from the console and ran to the pay phone at the station to call my house and ask my parents where the "gas switch" was. My mother couldn't figure out what I meant until she suddenly goes, "wait, you mean the button to unlock the tank? It's on the floor by your door."
...and that was my first-ever experience with a 'power-lock' gas tank.
Joe P.