Trjtdtk

Traditional tonal music plays with expectations.

Music can do many surprising and unexpected things, but very often music will do what is "expected" meaning that it follows certain conventions.

Let's switch to a language metaphor just for a moment.

If I say "hello, what is your... ", what word do you expect might be next? Do you think "name?" Certainly you would not expect "rhinoceros", you wouldn't expect "hello" to be repeated. Words like those would be unexpected.

In a similar way music has it's own grammar and syntax, and that grammar and syntax creates expectations for a listener.

So, if I play a V7 chord, it sets up an expectation for a I chord. I may or may not play that I chord, but an expectation is created. You expect to next hear notes from that I chord... and there is a very good chance you will hear them.

Other kinds of expectation can be created. If a melody goes up, eventually it will probably go down. Step-wise movement often continues in one direction. If a melody goes up as DO, RE... there is a reasonable chance that MI will follow. Call and response and other repetition devices also play with musical expectations.

You can’t predict only the next tone. Very often you can even tell or guess a whole phrase.

Melodies are built of motifs. These are elements that can be repeated, sequenced or brought back in an inverted form. Music theory and the theory of melody-building that describes the structural principles of melodies call it “question and answer” or “response”, “motif and development”:

If you have checked the motif

do so do sodosodomiso

you can construct e.g. 2 answers:

fa re fa re faretire so

or:

re la re la relarefa la

This can be explained by the inherent logic of a tune
and by principles of the melodic shape (“gestalt”) that are saying e.g.:

The whole is more than the sum of its parts.

Because Common Practice harmony is all about dominants resolving to tonics. About setting up tensions then resolving them. Here's a simplistic example:

You know where that penultimate chord wants to go. Often, you'll be satisfied!

Your question actually hints at what the "theory" in music theory is about. Following various combinations of notes, some continuations will sound smooth, some jarring, some relaxed, some tense, etc. Many people, yourself included, have an innate sense of what kind of continuation would best fit the nature of the music that precedes it, and much of the purpose of music theory centers around identifying what expectations will be created by various patterns in the music and, conversely, identifying what patterns in the music can be used to create various expectations.

Or, to put things another way, you probably have a sense of how the piece of music would go because the composer didn't want it to be particularly jarring, and music theory predicted that listeners who heard the heard the piece of music up to a certain point would find it least jarring if it continued in the way that many listeners, yourself included, would expect.

Satisfying music (like other art forms) dances on the border between order and chaos.

Music that's totally predictable and repetitive is boring to most of us; but so is music that's totally unpredictable and random.  The most enjoyable music tends to be that which combines the two: that has enough repetition and predictability to bring familiarity and structure, but enough unpredictability to add interest and surprise.  That's where complexity and richness lies.

Obviously, your ability to predict the next note, sound, chord, motif, harmony, or whatever will depend upon your familiarity with the genre, style, composer, &c.  So this is subjective.  (But that should be no surprise.)

So yes, if a melody is in a style/genre you know, then you'll have a non-zero chance of predicting the next note.  But if the music's any good, you won't always get it right!