Well, potential addiction, for one. Being cognizant enough to actually enjoy a weeks worth of Netflix, for two. And three, avoiding post surgery, um, constipation from the drugs... which I know of one case that was as painful as the surgery recovery.
Shoulder surgery is a very painful recovery. After a day on the hard stuff, my wife did fine alternating Tylenol and Ibuprofen because of the ice machine. When she had to stop icing because of frostbite it was straight back to narcotics.