Best friend

A Friend....
Accepts you as you are
Believes in "you"
Calls you just to say "HI"
Doesn't give up on you
Envisions the whole of you (even the unfinished parts)
Forgives your mistakes
Gives unconditionally
Helps you
Invites you over
Just "be" with you
Keeps you close at heart
Loves you for who you are
Makes a difference in your life
Never Judges
Offers support
Picks you up
Quiets your fears
Raises your spirits
Says nice things about you
Tells you the truth when you need to hear it
Understands you
Values you
Walks beside you
X-plains things you don't understand
Yells when you won't listen and
Zaps you back to reality

Which letter suits best to your best friend?