Degrees of Difficulty

So listening to a the revisionist history podcast by Malcolm gladwell, and he brings up the subject of degrees of difficulty as used in judging professional divers. I think it is relevant to any rpg using Difficulty Checks or assigning Target Numbers to tasks. The difference between the difficulty of doing a thing or doing a thing well are also discussed,  and I think that is extremely relevant to being a DM; it's easy to start DMing, but really hard to be a good DM. The relevant part of conversation starts at about the 15 minute mark