Meaning of Friend What a friend should be?

What a friend should be!

A Friend Should Be Radical...

They should love you when you're unlovable,
Hug you when you're unnavigable,
And bear you when you're unbearable.
A Friend should be Fanatical...
They should cheer when the whole world boos,
Dance when you get good news,
And cry when you cry too.
But most of all, a Friend should be
Mathematical...
They should multiply the joy, Divide the sorrow,
Subtract the past, And add to tomorrow,
Calculate the need deep in your heart,
And always be bigger than the sum of all their parts.