When we first arrived at the hotel, the door lock didn't open, so we couldn't get into the hotel for nearly an hour and had to shiver outside in the cold. However, the hotel staff did not know the cause and could not solve the problem.
We figured out on our own that the reason the lock didn't open was because it was frozen in the cold, and we were able to open it after warming the lock.
The second serious problem, the accommodation we used only had one bathroom. However, the shower was broken, so we couldn't shower properly for 2 days.