social/reddit

I think that you’re thinking of “sounding good” as being mostly relative to a fixed, un-changeing harmonic context. In this case the “key”. You’re thinking that because the piece mostly centers around the “key” of E major, that things will sound better the more that they are “in the key” of E major.

What you are hearing in this piece is that “sounding good” is more about the relationship of one chord to the next than to a fixed, un-moving “key center”. Songs can change key in the middle of them, or have multiple simultaneous implied key centers, and still sound good. “Keys” and “key signatures” are good to know in order to talk about music, but like someone else said they are descriptive rather than prescriptive.

If you create a nice melody connecting them, then you could make almost any two chords sound good one after the other.

In this case, this guitarist takes you on a journey through many different implied keys, but does it smoothly, and always ends up bringing you back to E major for a sense of resolution.

If I were to give you one thing to investigate to learn more about why this sounds good, I would say investigate “voice leading”. With proper voice leading, almost any chord progression can sound good, or at least coherent.