I was clearing out my laptop hardrive and paused when about to delete Morrowind. I couldn't bring myself to do it. Then suddenly remembered when I had replaced the exploration music with some choice tracks, particularly The Gravel Road from The Village. I can't listen to that song now without remembering taking my Daedric armoured character through the Ghost Gate and into the plague region. The Gravel Road started playing as I entered the region and what a poignant experience that was!
Or when I'd first completed the entire region edited heightmap for Mesogea and teleported into the centre then rode around for hours on end on a horse, exploring what had just been in my imagination. Astounding moments.
Yours?