Very popular. The thing is that humans tend to believe what they perceive, since there is no evolutionary reason for them not to. Some miserable wits have realized this and take it as their license to manipulate and deceive and feel superior, when, in fact, humans are not the sheep they claim to be, but they are manipulable, and they can be easy to panic when you know a couple of tricks. They are cheap tricks, though, and knowing them should not make a person as smug as it makes these fools.