Two strings walk in to a bar.
The bar owner shouts, "You two get out of here! We don't serve strings in this bar!"
The strings leave but, right outside the door, one of them starts banging his head against the sidewalk and contorting himself in crazy ways.
He walks back in to the bar and the bar owner angrily asks, "Hey! Aren't you one of them strings that just tried to come in here?"
The twisted, banged up string says...
"No, I'm a frayed knot.