I'm fascinated by song origins/motivations.
Some were written just for fun and really have no meaning (Elton John's Take Me To The Pilot).
Others have very deep meaning, and often much deeper and darker than you'd think (like Brown Sugar).
Fred Neil wrote Everybody's Talkin' in an effort to rush to finish his album and get back home (of course Harry Nillson made it famous).
CSNY wrote and recorded Ohio in less than 24 hours.
Billy Joel's "Prelude" portion of Angry Young Man was inspired by ELO's Fire On High.
Freebird was never really meant to be the long instrumental ballad that it is.
Late Lament wasn't meant to be linked to Nights In White Satin, but we always expect both to be played together.