First Off; The person who introduced me to and bought the tickets to see Peter Gabriel @ NYCity's Madison Square Garden's Felt Forum neglected (most likely intentionally) to warn me what to expect of what we'd come to see.
Taking our seat in the 2nd tier, we found ourselves more or less eye-level with an "In the Round" style of stage Lights went down music cued up; I found myself surrounded by 1,000+ devotees holding aloft lighted cigarette lighters (WTF?)
ASTOUNDING! I soon caught on that what I was seeingEXPERIENCING Wasn't "JUST A Concert" (a string of la-dee-da songs) but rather Performance Art set to An Entire Conceptual Piece of Contemporary Music ...more closely akin to a Rock Opera than any Rock Concert I'd ever experienced to that date**
**clavate: I've since experienced The WHO's Rock Opera known as "Quadrophenia"