A string walks into a bar.  The bartender says, “Get out.  We don’t serve your kind in here.”

The string leaves.  Once outside, he bends over and pushes his head through the loop in his belly.  Then he straightens up and tussles his hair. 

The string walks back into the bar.  The bartender asks, “Hey, aren’t you that string that I just kicked out of here?”

The string says, “No, I’m a frayed knot.”