First day of being in my college town. I still remember hitting the local trail that day before organized practice had started. The scenery was amazing, I was as fit as I had ever been, and I had four years in front of me to chase dreams. High School could not touch it and instantly became a distant memory.
Unfortunately I never amounted to anything in college and my best running memories (personally) all come from high school now when accomplishments are brought up.
If there's anything I'm nostalgic about regarding high school it's some of the dumb stuff I did and the people I did it with. Oh, and a girl of course. XC in high school was a great experience for me, I still talk to my coach, but after having been on a college team the nostalgia just isn't there for me.