"I Wish" (Stevie Wonder)

There's unmistakeable joy in every Stevie Wonder song.  It's not only in the lyrics or his unforgettable melodies, but it's also in the delivery.  The moment you hear Stevie's voice/keyboards/harmonica/drums/percussion, you feel the elation and love in every note.  Same goes for the performances of his supporting players; you can feel that those musicians were ecstatic to be playing alongside him.
Which brings me to "I Wish" from the near-perfect Songs in the Key of Life (1976).  
I've watched the 1997 Classic Albums documentary about the making of Songs in the Key of Life more times than I can count.  And I always find myself smiling when it comes to the part where Wonder is talking about coming up with "I Wish," which lyrically reminisces about simpler times and being a kid.
In short, he'd been attending Motown's annual company picnic—hanging out, eating food, and playing games with his extended family of label-mates, and it made him feel nostalgic for his childhood.  That same evening after the picnic, he went right into the studio with the tune already gestating in his brain, and he recorded "I Wish."
The repeating, 8-note riff that Wonder plays with his left hand alone is enough to make this one of Motown's best releases of all time.  But add in that galloping beat with the funkiest hi-hat pattern ever (also played by Wonder), Nathan Watts's stringed bass, and that buoyant big band-esque horn line, and you've got a timeless classic that never fails conjure memories of "the good ol' days."