Last summer, I spent a week of my holiday in a hotel in a small resort town close to the sea. In the room next to mine stayed a family - the parents and two children of elementary school age - who looked a bit stressed, especially the parents, but otherwise perfectly normal and not noticably different from any other guest.
However, I soon noticed something odd about this family:
Every morning, they would all leave their room on the 10th floor and take the lift down to the lobby on the ground floor to have breakfast. After they had all finished eating, they would take the lift back to the 10th floor and prepare for a day full of... whatever it is a family does on their summer holiday.
Every evening however, they would take the lift down to the lobby, eat, and afterwards take the stairs back to their room. This struck me as weird, because the lifts were all in perfect working order, and I used them myself within minutes of them disappearing into the staircase in order to get back to my room. One day I walked out of the lift just as they arrived at their door, all four of them sweating and breathing heavily, looking like they all had much rather taken the elevator than climb ten flights of stairs.
I did not dare ask them why they insisted on this strange evening ritual, but after thinking about it for a while in the silence of my room, the answer became clear.
So, what was the reason for my neighbour's behaviour?