Hm, I'd have to go with Mother by John Lennon. His mother had left him with her sister at age 5, and he didn't see her until much later. Soon after he reconnected with her, she got hit by a car and died. His father was never around and was overseas.
"Mother, you had me, but I never had you.
I wanted you, you didn't want me.
So I just gotta tell you,
"Father you left me, but I never left you.
I needed you, you didn't need me.
So I, I just gotta tell you, goodbye.
Heavy song to listen to. Wish John had a better childhood than he did.