What is a friend?

Friends,
What is a friend?
A friend is someone who will be there for you,
Some who will let you cry on their shoulders,
Laugh until you pee your pants,
Some who you can tell all your secrets with,
That's what our friendship started out to be,

He was always there for me,
Made me laugh when I felt down,
If I had to cry he would wipe away my tears,
We would laugh until we couldn't breathe,
and we trusted each other with our life,

But that all changed,
Instead of making me laugh he made me angry,
Instead if wiping away my tears he would just let them fall,
Instead of laughing he would say hurtful words,
Instead of trusting he turned his back on me,

Our friendship was never the same,
We thought our friendship would last a life time but who was I to believe that,
I guess some friendships aren’t meant to be,
You just never know when friends might turn their back and walk away,

So I ask this to you....
What is a friend?