I am curious to know what other people feel are the two or three factors that most hindering their enjoyment of reproduced sound???

To be sure, there is lots of discussion of equipment and media. And for me there have been time when these things have been my biggest irritant. (Still is with my HT set-up where speaker quality awaits my time & money for a DIY project I have in mind). But where my main system is concerned they have cease to be the big thing (for now).

My list follow; let's see yours:
  1. A distant first for me is recording quality. To be clear I'm not talking about medium, (vinyl vs. CD vs. high-res); good and bad recording exist on each. As a mainly classical listener, I'm looking for a realistic semblance of an actual ensemble performing in a good performance venue. Is this too much to ask? It isn't; and I can say the obviously because such recordings to exist. Just last night I listen to a good Naxos recording: Witold Lutoslawski's Symphony No. 3 and other works, 8.553423, (Antoni Witt/Polish National Radio Sym.Orch). This is an unexceptional recording in some ways; it is a standard Red Book CD that was recorded ten years ago and its reproduction of, e.g., string sound isn't as almost perfect as some SACDs I own. However it has the essential quality I mention above, plus more than decent performance I would say: recommend. By contrast, last night I also listened to Elgar's Enigma Variations and Pomp & Circumstance Marches on Sony Essential Classics, SBK-48 265, (Barenboim/LPO): murky, airless, and lacking in dynamics -- a disgraceful reproduction that does not do justice to these colorful works. (IMO, a second rate performance too especially of the Pomp & Circumstance.)
  2. Second for me is my general listening environment. My main system is located where too much general household noise intrudes. Improvements will be difficult and costly.
  3. Third is listening area itself. There are bass resonances and, I suspect, secondary reflects that are significantly detracting from idea frequency response.
You can see that my equipment is nothing special, barely beyond entry level, but I have no serious problem with it. The tube versus solid state and digital versus vinyl debates are farcical from my perspective. My SS equipment can reproduce the best CDs almost ideally -- apart from the factors I mention above.