"Ain't No Sunshine" (Bill Withers)

I can't express my respect and admiration for Bill Withers enough.  If you want to know why I'm such a fan, just watch the documentary Still Bill (2009).  You'll see a portrait of an intelligent, humble man who also happens to be one of the best songwriters of the 70s.  He's also highly principled: instead of kowtowing to trends and giving in to record execs who kept telling him how they thought his music should sound, he simply walked away from the industry in 1985 and went to raise a family instead.  (In the film, he tells a story about a white A&R guy who tried to convince him that a cover of Elvis's "In The Ghetto" was going to be his ticket to a pop hit.)
My favorite track of his (largely because it's the first one I ever heard) still is "Ain't No Sunshine" from his debut album, Just As I Am (1971).  It's a deceptively simple song: a short phrase ("I know") that gets repeated a total of 26 times, bookended by a few short lines that (on the surface) are about longing for lost love.  
As a little kid, I liked the track because it was easy to learn and remember.  I also enjoyed the counting game that my mom would play with me, where she'd challenge me to count the 26 I know's.
But as I got older, I started to realize that "Ain't No Sunshine" isn't some torch song, where ol' Bill is pining away for his woman.  It's a song about the vicious cycle of dependency.
Withers pretty much confirmed this in a 2004 interview with Carl Wiser of Songfacts.com.
"It's pretty obvious what it's about.  I was watching a movie called Days Of Wine And Roses (1962) with Lee Remick and Jack Lemmon.  They were both alcoholics who were alternately weak and strong.  It's like going back for seconds on rat poison.  Sometimes you miss things that weren't particularly good for you.  It's just something that crossed my mind from watching that movie, and probably something else that happened in my life that I'm not aware of."
Musically, it's beautifully melancholy.  But it also grooves like crazy.  After all, he had 3/4 of Booker T. & The M.G.'s (minus Steve Cropper) + Stephen Stills backing him on the single.