I think the best golf courses reveal themselves over time. The requires repeated plays, preferably in different conditions.
A first time guest of mine at Ballyhack once remarked (over lunch), "That's one hell of a hard golf course." That evening, over dinner and after a second tour, he said, "That's one hell of a fun golf course." Options that aren't immediately obvious become apparent, gradually, and the initial impression of difficulty weathers some as preferred lines, subtle bounces, and strategic options begin to appear.
In a way, the fun is disguised - or at least overshadowed - by the initial challenge.
This is true at other places too. Pine Valley, Bandon Trails, and Tobacco Road all come to mind.
WW