Fromm: The Art of Loving

The two persons become well acquainted, their intimacy loses more and more of its miraculous character, until their antagonism, their disappointments, their mutual boredom kill whatever is left of the initial excitement.

Yet, in the beginning they do not know all this: in fact, they take the intensity of the infatuation, this being "crazy" about each other, for proof of the intensity of their love, while it may only prove the degree of their preceding loneliness.

There is hardly any activity, any enterprise, which is started with such tremendous hopes and expectations, and yet, which fails so regularly, as love.

If this were the case with any other activity, people would be eager to know the reasons for the failure, and to learn how one could do better - or they would give up the activity.