It was Heraclitus that said, “No man ever steps in the same river twice”. He is was right, as subtle as it may seem, the same river is actually slightly different from the moment you stepped in it. I discovered this morning, while listening to the same song I listen to just about every day, the song was slightly different. Yes, if you have different speakers or monitors, the song sounds slightly different. Even where you are standing with same speakers, it will sound different. But it’s also an emotional difference as well. I found that I was in a much better mood this morning than usual and the same song sounded so much more different. I want to be the first one to coin the phrase, “The better your mood, the more you can hear.” Whether I am writing or composing a song, or producing it, my mood effects what I hear. When I am not happy, I cant’ seem to hear the sounds as well and I tend to doubt everything I am doing and every direction I try to take the sound in. So whether recording, editing, mixing, mastering or listening, depending on your mood, it’s never the same song.
I think I can relate to that, though I’d suggest it could be more complicated than just mood. That’s certainly a factor, but I would look also at the ability to focus without distraction. If your mood isn’t good, it’s likely because something is weighing on your mind or taxing your thoughts (even subconsciously) and so you won’t be as focused. There’s something called “focusing illusion” which simply means the thing that’s right in front of us seems most important, but if your mind is in other places it won’t have that focus and clarity. Also, there are brain chemical that contribute to being “in the zone”, like dopamine and serotonin etc.
There’s also oxytocin. No, it’s not a synthetic opiod (that’s oxycontin). 
It’s the “love hormone”, and while this might seem a little strange, I think having feelings for music can be a type of ‘bonding’ and like having a lover. Same type of feelings anyway. If you wake up next to the same person every day, some days will be great and some not. Did they change, or did you change? Or did both of you change? In this case the music probably didn’t change, so you have it as a mirror of yourself and your brain and what is happening inside you.
Interesting challenge: When you listen to that same song every day, write in a journal each day what your impressions and feelings are. See what changes from day to day. It could be very insightful and fascinating. 
That is why so many people say, “I LOVE this song” 
I have a couple of youtube playlists and they are made up of songs that create a great work background feel to them. I find most of the time I listen to the same playlist, even though I have 20 plus playlists. So it’s actually the same 50 songs or so every day. I will pay attention to one of them for a week and see.
I won’t deny that mood plays its part, but giving your ears a night’s rest is a very large factor in hearing a mix well.
If I’ve spent many hours on a mix, then listen to it first thing in the morning after a good night’s sleep, I can hear “wrong” stuff easily and put it right very quickly.
Interesting topic.
Yeah, our mental state will alter our attention and perception wildly. Have you ever listened to a song that you’ve loved , and then all of a sudden you’re not getting that euphoric rush from it all of a sudden? Maybe you got burned out on the song…or maybe you’re just not in the proper mental state to get that feeling. I get the same thing with beautiful scenes of nature or women that I think are attractive…Some moments I’m just not feeling the vibe like I do at other moments. Sometimes you just become very aware of things that you hadn’t noticed before…You could look at anything in life and find the good or bad in any of of it. But damn I love a good looking woman and the beauty of nature!
It’s definitely a thing. I think a lot of what makes music evocative is in how much it connects with your emotional state. It becomes a symbiotic thing where the song gets more emotional weight from what you connect to it, and in turn the song adds meaning on some deeper level to what is going on alongside it.
I think a great example is film music. When that orchestral score comes in at a part of the film that’s a great emotional payoff, if you’re the romantic/ sentimental type (I am), it can bring a tear to your eye. If that scene had no music, it might not be as emotional, and if you heard the music on the radio as you battled through rush hour traffic to get to work, it might mean nothing to you.
It can be the same when working on your own music. I recently had a situation where, not to put too fine a point on it, I accidentally fell in love with someone. And while I was feeling that way, I wrote several songs. The love couldn’t go anywhere because of several very valid reasons (first and foremost being my wife 
) and so had to confront my feelings and knock them on the head.
And now I’ve got this bunch of half-finished songs and ideas and as it stands, I just don’t want to work on them because they came about as part of a particular mood/ mindset. So I’ve had to put them down for a while.
For me, it seems the longer I wait, such as a week or two, the more I find things that are just not right. If I wait over a month, and then listen, sometimes I just realize the song is just not a good song and that I was caught up in the moment with it. But yes, time lets you hear things, like the bass is too loud or an annoying symbol tone is just not working.
Totally. If a new song comes along at the same time to some emotional event, such as death or falling in love, it seem that song now represents that event. It’s like the trademark of the event.
Don’t you just hate when that happens? 
I am going to guess that you will probably never pick them up again. I know for me, it would be like going back to something I want to forget.
A pinch of narcissism might save them yet!
An interesting dilemma. It reminds me of “Monogam-ish” which I think is a very valid approach to relationships. Basically “Monogam-ish” is functional monogamy (like marriage) but opens the space for human beings to express their feelings and vulnerabilities more. In other words, in a “Monogam-ish” relationship you would be able to tell your wife about these experiences (if you haven’t already) and discuss what it’s all about for you, and what it brings up for her. I understand it could be weird for one or both of you if you continue on with the songs, unless you opened up to something like “Monogam-ish”. It’s being able to explore the deep parts of ourselves that we don’t always allow other people to see. Certainly it may not be for everyone, it requires a deep exploration of core beliefs. Just a thought.
And speaking of which, is that what keeps us from writing really honest songs and actually using them? Sparing people’s feelings or being politically correct? Just a philosophic tilt on what the purpose and meaning of art is. 
For anyone curious about “Monogam-ish”:
.
I did talk to wifey. I figured if she is my best friend, it’d be silly not to talk to her about it - because it was starting to upset me a little. And it helped. And with her blessing, I talked to the other person too because we’ve been friends for nearly 20 years, lots of shared history etc. I’m not going to pretend it wasn’t a really bloody weird week, but I’m glad I spoke about it. If anything it made me feel closer to both of them, because the act of being honest, I think helps forge a stronger connection.
Time will tell whether it was a good idea, or really stupid. 
It’s a very good question. I think there’s a way of dealing with potentially contentious subjects, which is simply to obfuscate the meaning behind layers of, shall we say, ambiguity or vagueness or metaphor or whatever.
This is probably a good idea anyway, unless you’re writing songs purely as diary entries for your own benefit - if you want other people to relate to the art, you need to leave enough space for the listeners to place themselves in the art you’ve created. And it also means that it can continue to have meaning for you as the creator, after you’ve moved on from the mood/mental space you were in when you wrote it.
Good man! I know it’s not easy, but they say vulnerability is actually a strength … contrary to standard protocol.
Now that I think about it, this really came up for me the other evening. I think it was all the asteroid stuff NASA is putting out, the ones passing near Earth, and then the climate stuff and all the political frenzy - I thought about that song by Tool; AEnima. He gets very real about the world going down the toilet, frivolous modern life, and finally the asteroids plunging down on us that takes things back to the Stone Age - tidal waves and Armageddon (“learn to swim”). Their stuff was really weird but quite popular, at least with the Metal and progressive Rock crowds IIRC, including that song. Probably didn’t get on the Pop charts though.
.
I think I just accidentally fell in love with this woman in the Monogam-ish video. 
. What did Wicked say about a beautiful woman again?
Yes, she’s … um … quite stunning.