"He thinks great folly, child,' said Aslan. "This world is bursting with life for these few days because the song with which I called it into life st… - C. S. Lewis

When you are happy, so happy you have no sense of needing Him, so happy that you are tempted to feel His claims upon you as an interruption, if you remember yourself and turn to Him with gratitude and praise, you will be — or so it feels — welcomed with open arms. But go to Him when your need is desperate, when all other help is vain, and what do you find? A door slammed in your face, and a sound of bolting and double bolting on the inside. After that, silence.

"Friendship arises out of mere Companionship when two or more of the companions discover that they have in common some insight or interest or even taste which the others do not share and which, till that moment, each believed to be his own unique treasure (or burden). The typical expression of opening Friendship would be something like, "What? You too? I thought I was the only one."
... It is when two such persons discover one another, when, whether with immense difficulties and semi-articulate fumblings or with what would seem to us amazing and elliptical speed, they share their vision - it is then that Friendship is born. And instantly they stand together in an immense solitude."

Friendship is unnecessary, like philosophy, like art, like the universe itself (for God did not need to create). It has no survival value; rather it is one of those things which give value to survival.