I’m gob smacked. What were you’re aha moments?

Upgrading to Aragon Iridium monoblocks and then playing Yello - Flag vinyl through them... mind blowing

Two gobsmackments:  (1) wires.  Never knew what they could do for a system.  Most cost effective money you can spend on system upgrade.  (2) the difference a preamp can make in a system.
Jim Heckman

Like others, my “gobsmacked” moment has been with going from SS to tubes.  I’m more on the “starving artist” end of the audiophile spectrum, but managed to snag a pair of speakers very early on (JBL L65s) that have quieted any serious upgrade-itis for over 40 years and a refoam.  Over the years, these speakers have been fed with a procession of source components too lengthy to list.  They’ve been powered with (in order) a Pioneer SX-1250 receiver, a Denon PMA 700V integrated (a somewhat lesser gobsmack moment relative to the SX-1250), and a “brief” foray into the realm of multi-channel, audio/video receiverdom (a Sony GA7 ES, bought in 1997 which is still going strong and will see service in another room).  All these have been severely upstaged, however, by the PrimaLuna Prologue Classic tube integrated I brought home last weekend!  I am left simultaneously smiling from ear to ear and grieving for all the years I lost not switching to tubes.....of course everyone’s ears/preferences are different but I seem to have stumbled upon another genuine audio-related keeper-for-the-long-haul.  My ‘65s are now being fed by a Music Hall MMF-5 turntable & pa1.2 phono stage > the Prologue Classic.

40+ years of getting closer.  New house in 2000...lights dimmed when major appliances kicked in...Central Maine Power Company comes, tests, following Sunday at 10am a crew installs a new transformer (WITH NEW GROUND) outside house.  Most recent, Furutech products to 10amp dedicated line, outlet/cover & male end to line conditioner and Nano Fluid to EVERY metal to metal contact.  When it comes back from my friend, driver connects to Salks & Blue fuse contacts...I describe the changes to audio pals, "imagine upgrading all pc's, interconnects and speaker cables...at one time!"  Happy tunes and may all your harmonics be even, Lads.  Pin

8 kilo bronze platter for Garrard 301. Amazing detail and soundstage .                 Vcap coppers in Cary 300sei.. took 20 minutes max to install. smoooth midrange with bass extension I never thought possible with 300 b tubes