Music simply has several values, naming a few, social, historical, and emotional. Any type of music can be linked to previous or past experiences as it relates, again, to some sort of historical values. There are lots of literature that discuss this in terms of musicology, psychology, and even social sciences.

Hello Reza

I just thought this poem could be relevant :

Return Of The Salad Days

What happened to your salad days?

We look back at our lives,

We live in the past,

We look at the mirror,

Our faces the mysterious museum of last encounters,

We go down the memory road,

The path of desires, hearts and minds,

Of shames, remorse, betrayal and guilt,

Of laughters, love, songs and cries,

Of rawness, and spiciness,

We suppress the shame, we shall survive,

Days of hot kisses, magnetic hugs, devilish touches,

Of beloved’s stories, secrets and scandals,

We want to reminisce on the importance of growing up,

To indulge in the joyful recollections of the past,

To remember the good old days,

Return of the salad days,

Return of the salad days,

Return of the salad days,

The sweet milky moments,

Days of lust, zeal, and fun,

Lush moments of bless, flesh, blood and fire,

And we want to forget bad days,

Remove past wrongs from our memories,

Yes, I have made inks out of your tears,

Music out of your laughters,

Water of life out of your kisses,

Fire of hope out of your fever,

Books of wisdom out of your words,

Elixir of youth out of your eyes,

A healing lotion out of your sweat,

Let’s swim in the river of Lethe,

Me mnesikakein, forgetfulness and amnesty,

Let’s take the path of music, passion and pillow,

We are song worthy, love worthy, and kiss worthy,

Not shame worthy, not pain worthy and not hate worthy,

Salad days shall return,

Return of the salad days...

Ali Rahimi

on what basis is the music considered 'sad'? Some music is more inward and thoughtful rather than 'sad' as such. Music can give or appears to give expression to or chime in with a mood that someone is in and so they feel understood or comforted. There is quite a lot of research into 'music in everyday life' and how and why people listen to what.

This article of Kawakami establishes a clear independence between the emotion received and the emotion felt. It is clear that sad music produces pleasure, but the specific mechanism is not clear yet. Good luck!

https://www.researchgate.net/publication/240306963_Sad_Music_Induces_Pleasant_Emotion

Article Sad Music Induces Pleasant Emotion

While it can be hard to say for sure that a piece of music is "sad" or "cheerful" or anything else, assuming we can, the responses to "sad" music are complex, and as noted above, not always negative.

The recent suggestion seems to be that approx. 1/3 of responses to sad music are truly negative. The response can be positive if the listener feels as if they can relate to the musician and feel comfort from the music. As you suggest, these responses seem to be to music that is very familiar to the listener. The level of empathy in the listener also seems to be an important factor.

You may find some interesting insights in this paper.

All the best.

https://www.researchgate.net/publication/303963156_Memorable_Experiences_with_Sad_Music-Reasons_Reactions_and_Mechanisms_of_Three_Types_of_Experiences

Article Memorable Experiences with Sad Music—Reasons, Reactions and ...