My favorite song from the Wicked soundtrack is For Good, because I love the concept behind these lyrics:
I've heard it said
That people come into our lives for a reason
Bringing something we must learn
And we are led
To those who help us most to grow
If we let them
And we help them in return
Well, I don't know if I believe that's true
But I know I'm who I am today
Because I knew you...
Who can say if I've been changed for the better?
But because I knew you
I have been changed for good
So much of me
Is made from what I learned from you
You'll be with me
Like a handprint on my heart
And now whatever way our stories end
I know you have re-written mine
By being my friend...