Very true Jane, but I don't think "friend" is a way to address a girl that you are singing a love song to. Like I have said, I think they are singing love songs directly to everyone who listens, as we are all the receiver. We are all the friend, the girl, the darling, the baby, the her, the she, because we are the receiver. Metaphorically, the female is the receiver.
Check out this excerpt from "The Present" on page 213:
"Second coming: They are coming back, but not as the cute mop tops we saw the first time. This time we will see them for the prophets they really were and hear the spiritual and truth side of their music. It will change the world again. The power and vibe is still there; add the truth and the life (the present), your new perspective and you have a door to the magical mystery tour, a ticket to ride.
The long and winding road that leads to your door; they mean your door, your spirit. When they say I want to be your man, it means they want to be your mind.