You're tied to the dock and you've just finished lunch at your favorite waterside restaurant. The wind has picked up significantly and changed direction. It is now blowing you away from the dock. With the wind this strong there is no way to hold the boat to the dock once the lines are untied. How are you going to untie the lines from the dock and jump on board without taking the plunge? Simple, make sure your boat is tied off to the dock properly. Attach one end of your line to a boat cleat, make one turn around the dock cleat and go directly back to the same boat cleat to secure. With everyone aboard start your engines and make ready. Now you can just "slip the cleats". Untie one end of the line, and as the boat comes away from the dock you can pull in the lines as they slip around the cleats.
Happy Boating!