La tristeza se me pasa cuando escucho música y hablo con mi mejor amiga.

In this sentence, se me pasa means something like it goes away for me, it passes, or more naturally, it wears off / goes away.

So:

• La tristeza se me pasa = My sadness goes away / The sadness passes for me

This is a very common Spanish way to talk about feelings, pains, moods, and temporary states going away.

Similar examples:

• Se me pasa el dolor. = My pain goes away.
• Se me pasa el enfado. = My anger fades.

Spanish often expresses this idea less directly than English.

They do different jobs.

• me = to me / for me
• se is part of the pronominal expression pasarse in this kind of meaning

So se me pasa is not just random extra pronouns. It is the normal structure for saying that something passes or goes away for someone.

You can think of it roughly like this:

• La tristeza = the sadness
• se pasa = passes / goes away
• me = for me / from me

In more natural English: The sadness goes away for me.

Also notice the order:

• se me pasa
• not me se pasa

That order is fixed in Spanish when these pronouns go before the verb.

Spanish often uses the definite article with abstract nouns more than English does.

So la tristeza literally means the sadness, but in English we often just say sadness or my sadness depending on context.

Here, la tristeza refers to the feeling/state of sadness in a general but specific-to-the-situation way. Spanish is very comfortable using el / la with emotions, body parts, and abstract ideas.

Other examples:

• La felicidad dura poco. = Happiness doesn’t last long.
• El miedo desaparece. = Fear disappears.

English often drops the article where Spanish keeps it.

Because the subject is la tristeza, which is singular.

The thing that is doing the passing is la tristeza, so the verb agrees with that noun:

• La tristeza se me pasa. → singular subject → pasa
• Las penas se me pasan. → plural subject → pasan

The pronoun me does not control the verb. It is not the subject. It just means to me / for me.

Because Spanish usually drops subject pronouns when they are not needed.

The endings already show who is doing the action:

• escucho = I listen
• hablo = I speak / talk

So Spanish does not need yo unless you want emphasis or contrast.

Compare:

• Cuando escucho música y hablo con mi mejor amiga... = normal
• Cuando yo escucho música y hablo con mi mejor amiga... = more emphatic, like when I listen...

Omitting yo is the most natural choice here.

Because música is being used in a general sense here: music in general, not a specific piece or set of music.

So:

• escucho música = I listen to music
• escucho la música = I listen to the music (specific music)

This works very much like English:

• I listen to music = general habit/activity
• I listen to the music = specific music already known in context

Because hablar con means to talk with / to talk to, while hablar a is much less common in everyday conversation and sounds more formal, literary, or one-directional.

In normal spoken Spanish:

• hablar con alguien = to talk with/to someone

So:

• Hablo con mi mejor amiga. = I talk with/to my best friend.

You will hear hablar con much more often in ordinary speech.

Because this sentence describes a general, repeated, or habitual truth:

• When I listen to music and talk to my best friend, my sadness goes away.

It is not talking about one single occasion only. It means this is what usually happens.

So Spanish uses the present tense:

• se me pasa
• escucho
• hablo

This is very natural after cuando when you mean whenever or when in a general sense.

Yes. When cuando refers to something habitual or generally true, Spanish uses the present tense.

Here it means something like whenever:

• cuando escucho música y hablo con mi mejor amiga = when/whenever I listen to music and talk to my best friend

But if you were talking about a future event, Spanish often uses the present subjunctive after cuando:

• Cuando escuche música, me sentiré mejor. = When I listen to music / When I do listen to music, I’ll feel better.

So in your sentence, the regular present is correct because it describes a recurring situation.

Yes, you could, but it sounds a bit different.

• La tristeza se me pasa = more neutral, more idiomatic, very natural
• Mi tristeza se me pasa = more personal, a little more explicit or emotionally marked

Spanish often prefers the article where English might prefer a possessive. This is especially common with feelings, body parts, and states.

So la tristeza is the most natural version here.

No, that would not sound right with this meaning.

To express sadness goes away / passes, Spanish normally uses the pronominal structure:

• La tristeza se me pasa

Without se, pasar usually means things like:

• to happen
• to pass
• to spend time
• to pass something to someone

So the se is important here because it helps create the meaning of something fading or going away.

Yes. A very common alternative is se me quita.

• La tristeza se me quita cuando escucho música y hablo con mi mejor amiga.

That also means my sadness goes away.

A slight difference:

• se me pasa = passes, fades, wears off
• se me quita = is removed, goes away

In many everyday contexts, they are very close in meaning. Both are natural.