just 3 chords
Woody Guthrie is often quoted as saying "Anything more than three chords is just showing off." And then there's the quote attributed to any number of country singers, but I think Willie Nelson said it, "Three chords and the truth -- that's what a country song is."
My favorite is the joke, What's the difference between a rock guitarist and a jazz guitarist? A rock guitarist plays three chords to an audience of thousands, a jazz guitarist plays thousands of chords to an audience of three.
There's no doubt that some of the greatest songs ever use three, maybe four chords, but I find myself drawn to songs that are harmonically rich. Even the blues, which we often think of as just three chords, is really an overlay of flatted 3rds, 5ths, and 7ths on those three chords.