When have A/B comparisons led you astray?

Blindjim - wow! Thanks for the answer, everybody.
It's a strange fish to fry, isn't it?
What I do is forget all about A/B'ng. I'm more with Elizabeth on this one. I just make a change.
I DO NOT LIKE Stereo Stores and if they're scared to turn it on, what about me?
Let IT GO!
So far I have been moving towards the dry which is nice in a wet climate?
Seriously, though, thought does go into it.
I read in another post a serious exposition that to know less is more - or ignorance is bliss?? What I know of musicians minds is that they are better at integrating the R and L halves of their brains than just about anybody else. (Could this be tested with the Stroop test?)
I'm confused by things that don't make sense, and there are a lot of things within music that do make a lot of sense. They are usually what the music is about -impressionism aside.
I'm sorry to digress. These are source issues.
So what do YOU say?

Sure, this is a broad topic... It's a struggle for me to remember what it was like before I was married.
But what I am interested in here is comparisons made within a Stereo System.
I do think that my impressions at least 1 week after a change has been made are more useful than my initial impressions - at least sometimes. This is one of the areas where it gets sticky. There are so many variables that initially a change for the worse may be a change for the better. But where do you get off this wheel?
For example, if you add a cable from the D/A that dries things out - it may sound worse, but is that a good thing?
The most I can say is that the more I am aware of the effects each component has on the sound the more I can perhaps predict the change the swap will make.
In the end is there no reality to this artificial medium?
I hear that 78's are awesome! I have some experience with Mono and I have heard at times more reality with my system in that format than I have ever heard from stereo.

Last night I went to my son's Violin Master's Class.
Small venue - maybe 10 to 15 people present.
Piano and violin, that's it.
I have been listening to my digital source lately at home. I'm having trouble figuring it out. I know it doesn't sound real to me, but why?
What I am getting at is last night I feel like my ears woke up - again. The real sound is hard to describe but I feel that I am developing a sonic memory for it through training.
Ear training. My A/B comparison is moving toward Live vs. Recorded. Live is not a shifting reference. It is repeatable.
The Master's teacher was speaking about chords on the violin last night. A single note is in tune with itself. Only when compared or contrasted with another note can it be said to be out of tune.
To play a chord correctly on the violin, hold one note fixed and adjust the other to tune the interval.
So I agree. Does your system sound like live music?
Time will tell.

Have you never - even for just one song - mistaken it for the real thing?

How about when you shut your eyes, can you imagine that you are in the venue?
Sometimes I can.
With digital it's like I'm there but pixillated.
With analog, sometimes it works but usually there is smudge.