As an aspiring songwriter, 30 years ago or so, the new "confessional" songs of Joni Mitchell and Jackson Browne really gave me something to think about. They just blew away the ceiling of what I had considered a song could/should be. This was music that - for me - really turned rock music into something important, something of lasting value.
If I had to pick one song from that period that contains the elements that moved me so, it would be Jackson's " Opening Farewell ". It was just so different, so beautiful.