Why are there so many songs about rainbows?

Why are there so many songs about rainbows?
And what's on the other side
Rainbows are visions, but only illusions
And rainbows have nothing to hide
So we've been told and some choose to believe it
I know they're wrong, wait and see
Someday we'll find, the rainbow connection
The lovers, the dreamers and me

Who said that every wish would be heard and answered
when wished on the morning star?
Somebody thought of that and someone believed it
And look what it's done so far.
What's so amazing that keeps us stargazing?
And what do we think we might see?
Someday we'll find it, the rainbow connection
The lovers, the dreamers and me

All of us, under its spell
we know that it's probably magic...

Have you been half asleep and have you heard voices?
I've heard them calling my name.
Is this the sweet sound that calls the young sailors?
The voice might be one and the same
I've heard it too many times to ignore it
It's something that I'm supposed to be
Someday we'll find it, the rainbow connection
The lovers, the dreamers and me