Three pieces of string walk up to a pub on a bright sunny day and decide to enjoy a pint or two in the beer garden.
The first piece of string enters the pub and asks the barman for three pints of beer.
The barman says: "We don't serve pieces of string here. Bugger off."
The piece of string returns to his friends, upset at his failure and sobs at the table.
The second piece of string goes in and demands three pints and the barman says:"Bugger off. We don't serve string here."
The second piece of string bursts into tears and returns to his friends.
The third piece of string is so furious at the treatment his friends have received he storms into the pub, all wound up and furious and screams at the barman to give hiim three pints.
The barman glares at him and says: "Are you a piece of string too?"
And the piece of string says: "No, I'm a frayed knot."