Home alone today so I decided to chop up a lettuce salad with spinach, onions, green peppers, cuckes, tomatoes, etc. I'm old fashioned so I buy head lettuce as I don't care much for the bagged stuff. Anyway, I've struggled now for 72 years with the tiny knot that ties the plastic wrapping the head. Once every other decade or so I can unravel that knot, but mostly I just give up and use a knife to cut it open. Why do they wrap it that way, and what is the trick to unsnarling the damn thing?