I think what moves me often in a piece of music is the moment when the composer has lost himself slightly, in space or the deep vastness of thought momentarily & the composition varies on near madness, like a moment in Ravels Piano Concerto in G near the ending on the erratic notes of someone angry enough to loose their mind over something, someone - but controlled enough to be or know that they're in love or that they love - that this erraticism is known & controlled because it is written down in its containment, it's written down as the moment not necessarily to be understood but the genius of time, some divine spark that spoke, that is suddenly known yet will never be known because it is fleeting, that moment for us, for him/her, the composer it's gone & it will never exist anymore.
Moments in Scriabins Piano Concerto of extreme climax, some of Brahms' devotional love notes (letters) & the yearning finishing finalities of Saint Saens Organ Concerto.
It's that genius of the composer when he has loved his art or composition that much that he has abandoned himself to the collective perfection of the moment, where he hears every single note of every Animal, Plant, Sky, Sea, Person, Colour around him even in an empty room.
Where even the purest & perfect moment where even a Sunbeam or Moonbeam lights up a colour to set it on fire within its surroundings & it bounces into his open soul like a new country & his music comes to life. That's why we get stuck in a picture, why sometimes Art, a picture remembers itself in time & collaborates with the present to mirror, entrap or catch even itself off-guard.
That memory like a curse is like a repetition but can never be repeated how it was, never completely the same because it doesn't exist anymore & it never will, ever, ever again!