Despite centuries of human-ghost interaction and countless spooky tales, we mortals still don't have any concrete proof of ghosts. Most ghost encounters can simply be explained away as coincidence or as a trick of the light. Others, though, have a little more terrifying permanence.
If ghosts really are a part of ourselves that we leave behind when we die, then it makes sense that they would seek out the living. It would also make sense if they still had some human tendencies, like hatred of their old job. That's exactly what it looked like in this security camera footage taken from the lobby of an office building in Singapore.
The footage was taken earlier this month on a clear day with no wind. It certainly looks to me like a ghost is trying to get revenge on its old boss.video-player-present
The only thing I can think of that would be worse than working in an office would be working in a haunted office. It seems management should have considered ghostly retribution before they fired this person.