Fahnsen:
Perhaps this is said before in this thread, but it can't be said too often:
Of course experience makes it easier to judge, and getting familiar with a certain component we might discover subtleties we might not recognize right away.
But:
1: There isn't such a thing as an exact memory of sound. Unless two sources are switch immediately, we are simply not able to compare the sound. What we compare, is our memory of the sound.
2: Changes in the acoustic environment will outdo any other changes anytime. If your speakers are moved only sightly, or even if you turn or move your head, the sound that reaches your ears will change.
3: Our expectations and prejudices influence our judgement. If we believe a cable to be better, chances are it sound better to us. Or it might be the other way: Because we can't really hear the improvement we expected, we believe the sound to be poorer.
The human hearing is not comparable to technological measurement. While different meters can do very accurate measurements of single aspects, beyond what's audible to the human ear, no meter can mimic the human mind's registration and processing of various simultaneous inputs. Still, every bit of information that's physical can be registered individually by a meter, and calculated according to the laws of physics. So even if it's impossible to measure 'what we hear', what's not measurable is not audible, in the physical sense.
Therefor, if someone claims to hear a difference between components (like cables) that should not, according to physics, cause any difference, the obvious reasons are that 1, the time elapsed between listening to the two samples was more than a few seconds; thus a real comparison actually never took place -- 2, the physical relation between the listener's ears and the sound source were changed -- and 3, the listener was biased in some way or other.
There's more than enough tests by now, to prove that alleged differences between cables vanishes, even for trained ears, when the aspects mentioned above are controlled. What's more, there's tests showing that people easily hear differences between two identical samples, if they believe them to be different.
Now you see I really don't agree with this.
3 examples.
1) I changed a vdh D102 III for a Chord Chameleon - similar priced cables at RRP. As soon as I put the Chameleon on I noticed a way heavier bass. Too much in fact and I've since changed to a Nordost Heimdall which is much better for my tastes.
2) I changed 6mm OFC copper speaker cables to QED SA XT. More detail, but too bright. Again I have since changed to match my personal tastes.
3) I changed Merlin Tarantula mains on my CDP to a Nordost Shiva. To say it was more revealing, far more 3D in sound is an understatement. I was, like you, not expecting to hear quite such a difference. But it was there. And before you ask I paid £74 on eBay 2nd hand for this cable so knew that I could sell on for more if necessary. Suffice it to say it's staying. Love it.
I have to say, and chalk and cheese is an overstatement, but a good cable can make a good difference. That doesn't mean all cables are good either.
Just to finish off, I do consider myself an audiophile. Yes I listen to and really appreciate music, and hifi makes this experience more enjoyable to me. I do enjoy listening critically, but it's not the be all and end all. For instance I am listening to a lot of Elbow at the moment, and they aren't great recordings but I enjoy them. Having said that if I was to want to show off my system, they would not be on the playlist.