In the song "My Favorite Things," the melody for the first line is the same as that of the second line. If you play the same chords for the two lines, it's musically very uninteresting. It is the use of different chords -- C major 7th instead of a simple E minor chord (in the key of G) -- that brings life to the (repeatd) melody in the second line. To me, this is an example where "Less Is More" doesn't apply. (You could use a straight C instead of Cmaj7, I guess. But play it both ways and tell me which sounds better.)