I think it was when I learned that the initial recording
was poor, not the fact that I was listening to a 320Kbps MP3 instead of a FLAC, was the reason I wasn't satisfied with the sound. Or my mind wasn't satisfied with it because I knew
I wasn't listening to a "lossless" file. With my headphone setup, I could maybe approach telling a difference, but after a while of A/Bing, it just isn't worth it to me. Double blind, like John mentioned
In my experience, when you "know" something is a supposably worse recording/format/cable/speaker/piece of equipment, your mind's ear will pick apart all of the "bad" sonic elements of a song -- even if it may have nothing to do with the setup change that you just made when trying to notice sound differences.
Once I got over that, I could finally just enjoy the music.
I would like to get into vinyl though...vintage analog sound