system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does a repeating sequence of notes sounds different depending on what note i start on?

If, on a piano, i play A-B-C-A-B-C-A-B... And so on, why does B-C-A-B-C-A ... Sound completely different, despite being the same pattern starting on a different initial note? Why does my brain make the first note i play seem more "dominant" on each playthrough? And why does the music sound different, despite essentially being the same?
gpt
Congratulations! You just discovered different musical modes. If you pick C as your "tonic" and go up to the next C, the sequence of whole and half steps results in something called a Major Scale, or Ionian mode. If you start on A, you get a Minor Scale, or Aeolian mode. The other modes aren't used as often. If you play the 1st, 3rd, and 5th notes of a mode, you get something called a "triad" or "chord". These chords, in major or minor, are the basis of all Western music. 

You are trained to hear the first note played as the tonic, because it almost always is. When you start on A, your brain assumes that whatever follows is meant to be heard in the context of A, so you hear it as the first notes of an ascending Minor scale. When you start on C, your brain assumes that whatever follows is meant to be heard in the context of C, so what you hear is the first notes of a descending Major scale. Similarly, when you start on B, you hear a cadence in the Locrian mode, which is wierd and almost never used in Western music because it contains a diminished 5th, which we've all kind of decided sounds really really bad ("the Devil's Interval", C to Gb, or in your case, B to F)