The first time my parents came to visit me in Tokyo, I gave them directions to my apartment and put the kettle on for a cup of tea.
While waiting patiently for them to arrive, my phone rang. It was my mother, saying she was outside my apartment and asking why I wasn't answering the door. I checked the door — nobody was there.
After some back and forth, we realized my parents were standing outside the right apartment number, but in the neighboring building.