Something strange always happen in my office at night after everyone goes home. My colleague who work late before used to tell us that even if she is alone, she will hear a lot of sounds of people walking and taping on the keyboard etc. It's strange. Most of us do not like to stay late at all. (Memory collected at the Cheng San Public Library during the "irememberGhost stories" campaign from 27 Sep to 30 Nov 2012)