Commitment to improvement. Not effort, plenty of that at every golf shop and range. Failure to establish and commit to a plan of improvement with the help of an instructor. There is very little honest self-evaluation in the game of golf. I have a friend who can hit a five iron 200 yards but cannot get out of a bunker to save his life or hit a soft pitch shot. Yet he never gets fitted for wedges properly or takes a short game lesson.