Numerous writers, poets, and philosophers have noted that as human beings we love others despite their faults. Love is not so much blind by nature as it is blind by choice. The lover chooses to ignore the shortcomings of his beloved.
This aspect of love points to the fact the love involves an exercise in consciousness. To love is to decide to love, to choose to love. What drives that choice is open to debate, but often the choice is made in defiance of evidence that would indicate to an outside observer that the beloved is not worthy. In other words love is not earned by merit but granted by the lover based on arbitrary and often unidentifiable factors, unknown in many cases even to the lover.
There are other common notions about love which run counter to the observations above. Many view love as something that must be merited by the beloved. The object of love must meet the emotional needs of the lover or else be rejected for non-compliance. Under this paradigm love becomes a transaction.
I give my love if you respond to that love in the way I require. Otherwise love will end. My love is conditional.
Unfortunately, this latter concept of love is really an exercise in selfishness. This view diminishes love to the point of impotence. It takes what is meant to be the greatest attribute of our spiritual nature and reduces it to just another weapon or tool in the arsenal of control and manipulation.