And the biggest influence on sound quality is...

BTW, taming a bad room may not require expensive and non-homelike room treatments. In overly reflective rooms (more common than overly damped ones), there are many steps one can make to control those reflections. Rugs, shades & drapes, soft furnishings, textile art. David Wilson told me long ago that shelved books and records make some of the best acoustic treatments.

Bass response varies tremendously around a room due to the effects of standing waves. Sometimes simply moving one's listening position a couple of feet in one direction or another can turn anemic bass into rich tuneful bass (or go beyond into flatulance).

While electronic room correction systems like Dirac can make a big difference, one is almost always better off first minimizing the sonic elements that need correcting.

Being present for the music.

I find this most influence (for me) is to be able to chill out and not listen with the "looking for imperfection" mindset I cannot seem to escape at times, and instead just turn the lights low, lower the needle (or whatever I may be using), and exhale. It’s a big ask.

Like for me zeroing in awe on a Ron Carter bass line or Elvin Jones brush wondering right in that moment, hmmm, perhaps there is a way I should lift the needle and play my other copy, search another master to stream, swap a cable, turn off all appliances, move those home made bass traps, move my paintings to other places on the wall.

Just not then.

On a more practical front, the master bar none.

Your room. The least sexy part of the process unless you can afford to hire a pro to do the whole thing for you. Most tweaks make micro differences, room treatment  is a macro difference. Huge in most cases. 

A wife that thinks 50k is a reasonable amount to spend on stereo gear for the living room....

You have your system and your room...but a good recording in a big open,wood floors won't really help.