In 2008, I was teaching in Prague. In-company teaching, which means that I used to go to my students' offices and hold lessons there. I was living in a small apartment tucked into a corner of a weird sort of building complex. Street-level there was a restaurant and next to it a big, heavy door. Through the door was a sort of courtyard, half taken up by a covered seating area for the restaurant, On the other side of that was a set of stairs leading to a locked gate. Through the gate was more stairs, then another gate, then more stairs. On each of 3 stair landings, there was a balcony that went around the courtyard with flats all around it. My flat was tucked halfway up the second flight of stairs, between the two locked gates.
So one morning I woke up before 6 because I had a lesson at 7 and my supervisor was going to be there to observe me. I'd planned it all meticulously and had a load of supplies, which I didn't usually bother with because my students weren't that engaged and it was a pain to haul everything around on public transport. I was so caught up in remembering all my supplies that I left my keys on the hall table. The door to my flat was the kind that locked automatically when it was closed. So I was trapped without my keys in between two locked gates at 6.45 am in a country where I didn't speak the language on the morning of my lesson observation. And I was out of credit on my phone so couldn't call or text anyone. Eventually, my supervisor called to see where the heck I was and I had to confess everything to her. She was Czech and called my landlord and arranged for him to come rescue me. I felt thoroughly stupid, AND I never got to use my beautifully planned lesson because the observation was postponed and a few weeks later I quit that job to get married and move to England.
There really weren't any major consequences since I hated that job and was glad to leave, but it's the dumbest I've ever felt in my life.