Who doesn't love a great brain teaser? To be honest, most people are infuriated by them because they seem so difficult on the surface, but once you actually find out the answer you are steamed that you didn't understand it right away. Basically it comes down to common sense and keeping it as simple as possible.
What I think bothers people the most about brain teasers with no basis in math or science and technology, is that there isn't always a clear-cut answer. I mean, you don't always have all of the information you would normally need to come up with an answer specific to what the question "wants."
Late last year, this particular "brain teaser" had the internet roiling in a collective fit of division and anger, with everyone thinking that they were right and all others were wrong. But what is lacking here is, "what type of a question is this?" Is it math, or what?
When you realize what answer they were looking for, it will drive you insane with its simplicity, but also because few people would guess what this actually represented.
Here's the question: What goes in the empty box? I'll give you a head-start, it's not six.