About an hour later, I went to the men's room. Which is in the building core, just outside the front entrance to our offices. The front that can only be opened from the outside with an RFID card in the form of a badge.
I reckon most of you already know where this is going.
We're not one of those companies where an employee's RFID badge doubles as an photo-id badge. So I keep mine, as I kept a similar one for several years starting sometime last century, in my wallet.
Thing is, thought i, as I stood there feeling a fool, I only ever needed that one to get me into the building after hours. Not to get back into the office from the men's room.
I was saved by ken_r, and when I mentioned "Now i know why so many people here keep their badges on those retractable clips," he showed me where we keep them. So I used that the rest of the day.