A piece of string walks into a bar and walks up to the counter.

The bartender says, "Sorry mate, we don't serve pieces of string in here, get lost."

Upset, the piece of string walks out the door. A sudden thought strikes him. He ties himself in a knot and messes his hair up.

He walks back into the bar and approaches the counter. The bartender says, "Oi, aren't you that piece of string from before...?"

"No," says the piece of string, "I'm a frayed knot."