The Old Course's routing is neat because it starts and finishes in the town and in between that you've got a wonderful golf experience. Mind you, not a visual extravaganza for the non-golfer, but an epic adventure for someone who truly loves playing golf.
You glimpse the magic of the course on the first hole. Drive is no big deal...wide open...no threats...other than this meandering rinky dink stream/burn. But if you watch people play that hole, a surprising number of then dunk their approach in that water. I'm sure they think it was just a random bad break...but I'd argue it is the perfect opener. Just easy enough to get you feeling comfortable, but just enough challenge to bite you if you are not mentally on your game and/or in the correct place.
And, maybe, that is the crux of what makes The Old Course so good. You think you are okay or you will be okay...but you are in the wrong spot. To get back in the right spot(s), then takes more doing than you were mentally prepared for...and you drop a shot.
But on your first go round (or 25 go arounds), it is difficult to truly understand where the correct spots to be are FOR YOUR GAME. And that is a big part of it, lots of strategies and, furthermore, tactical ways to try to take advantages of the different strategies. And, oh yeah, then execute the shots you choose to choose to play.
There are holes with centerline bunkers, acute spur formations, "unfair" greens...and when you add in the weather conditions how you might choose to handle those hazards can change from day to day.
To me, that is what I love about The Old Course. The layout, strategies, and tactics can change from day to day, yielding fun and different golf, but yet on the same course.
Courses like this are fund to play, but watching others play is a hoot as well.
And the apex of this "hoot" is the epic run of mind engaging and physically challenging holes on the back nine. Perhaps the very best in all the world.