I'm sure if John Denver had really "thought" about it, he'd have written...
"Rainbows on my shoulders make me happy
Rainbows in my eyes can make me cry..."
I swear that somewhere, some time, John Denver DID sing:
Sunshine on my shoulder gives me sunburn,
Sunshine in my eye can make me blind,
Sunshine on the water makes it lukewarm,
Sunshine almost always makes me fine.