What was the first system you heard that made you think the high end made sense

I was with a coworker who needed to stop by his mothers house while we where out. His step father was a modest fellow who drove a Lays Chips delivery truck, the house was a typical modest middle class home. While there my coworker asked if we could listen to his step dads set up. His space was a 12x12 room with a sofa toward the rear at center but well off the rear wall, with obvious room treatments. He was running Magnepans, a single two channel amp, a very basic pre, basically a volume controller, a CD player, and a 8inch bass cube. He mentioned he was running everything to follow the shortest path from the CD player to the speakers using only what was absolutely needed. He played Dire Straits Brother in Arms, it was fantastic. I immediately questioned the system I had at the time, a Best Buy Pioneer AV receiver with low end Klipsch towers. I got home fired it up and literally said to myself (this sounds like bad) and thus that’s where it started, Damn that guy.

Summer 1970 at my friend's house. A pair of Large Advents and a Kenwood integrated amp. Thorens 125 TT with Shure cartridge. Listened to Hendrix Electric Ladyland, Its A Beautiful Day, Procul Harum A Salty Dog. Audio bliss! Enhanced by taking acid!

Winter of 1970. Shacked up at a girl's house for a couple of weeks and she had in her living room a tube Fisher receiver and a pair of KLH speaker's. The sound had a very silky ultra smooth midrange that would stop you dead in your tracks. That got me hooked. One thing I will never get is this. When Henry Kloss left KLH and started Advent in 1968, his Advent design's were inferior to his KLH model's, especially the three way KLH model with its electrostatic tweeter that was the best model, and best sounding speaker him and his design team ever produced from 1964. I had a large pair of Advent's from 1976, which had much better bass slam than his previous KLH model's but the mid-range and high frequencies were no match against KLH. The Advent's were harder sounding and lacked the top end smoothness of KLH.

Marantz tuner, Garrard TT, and Superscope speakers circa 1977. My very first and favorite set-up. Wish I still had it. 

My late friend Courtney Carroll got me into audio way back in 1979-1980. He sat down with me and before listening for the first time we smoked some Colombian and it was on! I still remember that system. He had an ARC preamp and amplifier, Tympani 1D’s panels and using Mogami speaker cable. I have been into audio since that experience. ;)