Learned VERY FAST...back then, big manufacturers we carried spent time educating us on pretty much everything so we could sell more. I don't know what they do today, but B&O, Audio Research, Magnepan, Nakamichi, Sequerra, Tandberg, Sony, Marantz, Scott (remember them?), JBL, AR, Technics, Shure, Satin, Supex, AT, Revox, Crown, etc., etc. helped us immensely.
Probably my biggest personal surprises:
1. How poorly large Advents really sounded. We LOVED them in college, just like everyone from that era, I guess. No disrespect to Henry Kloss, truly an audio pioneer and did the best he could for about $95.00 retail!
2. How ridiculous Bose "direct reflecting" speakers sounded...we literally laughed out loud.
3. How Klipschorn speakers distorted everything, especially opera.
4. How "screechy" Crown and Phase Linear amps sounded. Crown stuff never lasted more than a couple of hours before blowing. Phase Linear was pretty bad as well--but, customers abused PL 700's quite a bit!
4. How Magneplanars, even in those days before many refinements like the Tympani IV-4 A, were a revelation when compared to any box speaker on the floor. Only close box choice would have been Fulton 100's. (Bob Fulton--along with so many, a great audio pioneer.)
5. Finally, and MOST IMPORTANTLY, that the customer's ROOM was the most important "component" of any audio system and always will be.
Long time ago...huge changes in many parts of the audio game. However, the objective remains the faithful recording and playback of live music or recorded music that adds and/or removes nothing.
Cheers!