I do this fairly often on a smaller scale. Switching to the wrong window, looking up the wrong phone number, giving the wrong person's name, etc. ("...Miki Takahashi" "could you spell that?" "Uh, A, y, u... no..." fortunately I didn't actually say the last part, I caught it in my head. )

I think there's only been a few cases where I've actually gone to the wrong place, and usually it's something minor like going to the wrong store in the mall. On the off chance I actually head out with the completely wrong destination in mind, I only get a few steps before I realize it. However, it won't be until I'm at least halfway there that I realize I forgot something. (Murphy's law. )

There was one time though I showed up to the wrong class twice in a row, but that wasn't my fault. It was the first day, and they moved the class without telling me, so I went to the room it had moved from. There was no work done that day (just introducing everyone), so it wasn't until the second day when the "math" teacher started handing out biology textbooks that I had reason to suspect anything. Though I wonder why they didn't see the issue on the attendance records.

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