A rope walks into a bar, and sits down. The bartender walks over, and tells it, "Sorry. We don't serve ropes in here."
The rope walks outside, and asked a passerby "Will you do me a favor, please? Tie me up, and unravel me a little bit. Then scrape me along the sidewalk."
The passerby complies, and the rope is definitely looking worse for the wear.
The rope walks back in to the bar and sits down. The bartender walks over and asks, "Aren't you the rope that was in here a few minutes ago?"
"Nope; I'm a frayed knot."