When someone listens to your system for the first time.
I recently had a 30 something friend of mine, I'm 64, stop in for a bit and sit in my listening chair. He is a musician and had never heard my system. Decided to play him Sultans of Swing on my turntable. He was awe struck. Look of amazement on his face. he said he had heard the song countless times, but now knew he had never really heard it. He talked about the clarity, how wonderful the cymbals sounded, how awesome the bass was (thanks to the new subwoofers I bought). I played him a few more things, some Tony Rice, to hear some acoustic instruments. He couldn't get over the soundstage and imaging. He said he knew why I sat in that chair. He said he wants to come back, there are tons of songs he wants to now hear on my system. I listen to music just about every night. I enjoy my system, but sometimes get caught up in listening to the gear, wondering if I should change something. Nature of the hobby. So nice to get a new perspective. Reminder to stop over thinking and enjoy the music.