A string walks into a bar and asks the bartender for a drink.
The bartender replies "I'm sorry, We don't serve strings"
The string, angry, runs to the bathroom and ties himself up into knots until his ends are frayed.
Then he walks back out and asks the bartender for a drink.
"Hey, aren't you the string I just talked to?" The bartender asks.
"Nope," Says the string, "I'm afraid not." (a frayed knot)