Real friends are useless.

You probably have some “deal friends”. 

These friendships are transactional.

You may work with your deal friends or do business with them.

They are fun, but if there is no “deal” you wouldn’t be friends.

As Harvard professor, Arthur Brooks, says, 

“Real friends are useless.”

So true.
That tickles me.

I plan on going out with some useless friends today.

Maybe I’ll make some more useless friends and have a useless friends party.

That sounds like the foundation of happiness to me.