It takes time to get the stink out of your ear

The same applies to bad gear IMHO.  At first clarity of new Benchmark DAC, felt strange.  I had impression that some instruments are missing.  I had to get used to it (learn to listen).  Others must've felt the same since one person commented "I can hear each instrument and I used to hear them together" (sound blob).  Another person asked how to make sound warmer and less resolving (blanket over speakers?).  Sound with added distortions or noise appears more vivid/dynamic, like distorted guitar vs clean Jazz guitar at the same volume.  We can hear what it should sound like at live performance, but at home we got used to different sound as a reference point.  It takes time to get the stink out of our ears (learn to listen).  

I've had this work both ways. I've listened to a great system, then gotten in a car and noticed my ears were now more willing to pick up notes I'd otherwise not.

Our ear/brain mechanism is inconstant flux.

NO never happen to me.