Mood and hormones are directly correlated to how you respond to external stimuli, sounds included.I'm not saying people are making this stuff up. If you believe you can hear an improvement, then fine. My point is, there is nothing physically different in the cable, which could possibly make this happen. One forum member a while back mentioned 'expectation bias' and you can make yourself believe many things. I recently cleaned all my kit, fastidiously making sure all the cables and connections and components were dust free etc. I reconnected again and believed I could hear an improvement in the sound quality. The following day, I wasn't sure if I could still hear this difference. The human mind can change your perceptions and I think it's this that changes how you feel about a particular sound and there is nothing fundamentally different with a cable, or fuse, or piece of wooden furniture etc. Mood and hormones are directly correlated to how you respond to external stimuli, sounds included.
Absolutely, there's a lot of truth in that, sometimes I listen to my music and I'm not enjoying it as much and on another day, I'm loving it.
Do we all live in a bubble? Probably