What steps forward were actually steps backward?

I agree with Drubin, Johnnantais's post is excellent, as is Mattybumpkin's. I've never been bothered by an upgrade to my system where I've had the piece in my system for an extended audition, which is almost all pieces these days (even my upgrade of my Audio Logic came with a promise from Jerry Ozment to undo the upgrade if I didn't like it). I don't really listen critically after the first hour of trying to hear what the objective differences are--after that, I just sit back and see how the music moves me for the next few days, listening to pieces of music that I like. I then reinsert the piece I'm thinking of replacing and see if I still like the upgrade better. Not an exact science, but it seems to work well--my Jadis JP80 withstood many assaults from objectively "better" preamps for years via this method. There is a fine line between revealing more information and losing the musical enjoyment; you can have them both, but there are not that many products out there that can perform this balancing act well.

Sold my Mcintosh MA6900 to "upgrade" to the more "audiophile" route. It was an interesting detour but I came back to the Mcintosh and eventually upgraded to tube Mcintosh separates. Just so damn musical. I got annoyed at losing money, but the experience was educational and education is always a worthwhile expense. I learned what I like and don't like (and what's overhyped).

Another set up that I upgraded from only to be disappointed was a Pass Aleph amp and an FT Audio passive pramp. Great for the money, great anyway. Just a little short on dynamics.

Drubin, the siren call of "impressive" is paved with misery, but it is a siren call. However, having one's cake and eating it too is possible, but I believe that amount of information is, for the most part, inversely proportional to how much music survives. To put it otherwise, the more detail a system retrieves, the more difficult it is to hold the music together, bordering on impossible. The late and lamented "Listener" magazine once ran a photo of a top-of-the-line Wilson speaker with the caption "There is a use for these!" - the photo showed one being hoisted up from the water at the end of a chain on a boat: it was an anchor! We reduce the importance of timing by dubbing it "Prat," thus offhandedly dismissing it. But a system without timing is good for nothing but boat-anchors, as Listener believed. Which is why that magazine attempted to review only musical equipment, with that missing "magic" factor.

The modern inexpensive int. amp (under $1800) which I've owned recently, haven't been all that great sounding especially given their cost.(The exception, a French Kora "Explorer" which IMO is an outstanding sounding amp) The sound quality of older Mid-80's Sony "Legato" int. amps is excellent and are absolute bargins used. My 70's Kenwood KA-7100 stills sounds/performs as new. Tuners haven't advanced at all, IMO. Since my introduction (early 70's) to this crazy hobby, I've come to the conclusion that great sounding/musical systems need not cost a fortune to assemble. Much of what we've been programmed to believe is not necessarry true. I see a big demand in older equipment! Without question, hugh steps forward have been made in IC/Spk./Power cables.

Wonderful comments so far about reaching the goal of enjoying the music when we listen, rather than merely unveiling the remaining inadequacies in a system, when we upgrade part of it.
The best upgrade would be one we can audition in our own system, before we irrevocably commit our money. I have made many "upgrades" based on faith in opinion of those more experienced, until finally reaching a point where I can feel confident deciding for myself.
Home trials, with their lack of sale pressure, have proven very valuable in forming my own preferences. Joining an audio club has also been of great value, unless you already have a neighborhood circle of audio buddies.
Although it seems too obvious to state, there is musical, and audio taste, so that each of us must protect our own sense of what is really enjoyable. In every field, a guru guides the novice to reach personal sophistication, even if it is not identical to the guru's view. At least the phrase rhymes.