I couldn’t help laughing when I came across this cartoon from the fabulous xkcd website:
If you get the joke, then congratulations, you know what a bi-conditional is, and you recognise formal logic when you see it.
If you don’t get the joke but are curious to know why it is funny, then stick around this blog for a while; logic is what it’s about.
If you don’t get the joke but still think you understand logic, you are probably a paranormal expert.
(The sub text to the above explains it all: “Note that this implies you should NOT honk solely because I stopped for a pedestrian and you’re behind me”.)