A piece of string walks into a bar....
And the bartender says "HEY!! We don't serve pieces of string here!! Get out!!"
So the piece of string goes outside, messes up his hair, rolls around in the gutter, and walks back in. The bartender yells "HEY!! Aren't you that piece of string I just threw out of here?!" And the string says "No, I'm a frayed knot."