Much of what we very commonly call "friendship" is not a form of love at all, and is really not much more than an exercise in a mutual self-serving immersion into the personal self. Unlike the English language, the Greek language used four words to describe variations of love.
"φιλια [A "Greek" word for love frequently translated in English as "friendship"] is the most concrete kind of love that a spiritually transformed individual feels and manifests. It is a spontaneous love, resulting from the reaching out of those no longer bound by the priorities rising from immersion into the personal self. It is readily observable, since it is so remarkable -- seen, as it is, in those few accomplished individuals who see Christ within themselves, who behold Christ in others, and who by nature direct the force of self-love towards others, since they are one with others by virtue of their unity with Christ, the One in Whom all dwell." (Bp. Chrysostomos, Love, pp. 26, 27)