Friendship is supposed to be non-transactional. That is, a true friend is someone who values the relationship itself over what s/he gets out of it. If you want

Friendship is supposed to be non-transactional. That is, a true friend is someone who values the relationship itself over what s/he gets out of it. If you want a rational explanation for this, think about how, in an alliance, you need to be able to trust the other person not to backstab you if you are temporarily weak. Most people pay a lot of attention to figuring out whether the other person values the relationship over what they're getting out of it. (Citation: all gossip, every Shakespeare play, all of literature generally).