One of the other reasons I have to leave the room when The Little Drummer Boy is played is the boring, repetitive, unimaginative melody line ("melody line", quote unquote). It is like water torture.

On the opposite side of the fence, the interesting melody, its twists and turns, and the harmonies in O Holy Night for me are sublime, IMHO.

And yes, I know some people cringe when they hear it, but it stops me in my tracks when it is beautifully performed.

IL DIVO - O Holy Night

Mahalia Jackson

And of course, again IMHO, there has to be a version with harp:
Celtic Trio and Choir - Emer Barry and Affiniti