[NOTE: This article is based on opinions of Internet users and not facts.]
Before you start rolling your eyes, hear me out. Just because we wrote this post doesn't mean we're condoning any sort of superstition or belief in the supernatural. But hey, whether you believe in ghosts or not, just try to play along.
Just remember, to a believer, no explanation is necessary; to the non-believers, none will suffice.
We trawled the Internet to see what people think are signs that indicate the presence of a ghost or a spirit around, and these seem to be some of the most common answers.