For me, it was Jeffersonville GC in Norristown, PA. I had been playing for a few years at a lot of different courses, but always enjoyed my rounds at J-Ville a lot more than the other places I played. I looked into who designed the course and found out it was Donald Ross, so I started reading more about him and sought out his other courses. The shapes of the holes, placement of the bunkers, greens; realizing it all had a purpose of strategy and aesthetics, I started looking at golf in a whole new, and refreshing, perspective.
As the years went by and I dove head first into learning and experiencing all I could on GCA, becoming more enraptured each day, J-Ville underwent a good amount of improvements, including much better conditioning, that eventually earned it top 10 status in PA with Golfweek. Regardless of the ranking, it is still a no frills muni that you can walk for less than $20 during the week and remains one of my favorite Ross courses. I enjoy going back each season and playing it as my own GCA experiences evolve and grow to see how it changes for me.