Love is the only answer to the question of human existence. It is the feeling that unites hearts and souls. Life would be meaningless, if love wouldn't exist. It is a feeling that gives many of us a reason to live. Love may sometimes seem to be life's most intense emotion, which is difficult to track. Sometimes, you may become clueless about whether love is controlled by the heart or the feeling itself has occupied your mind and soul! When you are at this situation and are in search of an answer, just think about what how much love is vital in your relationship.
Any relationship in the world, be it between a couple, siblings or friends, will be incomplete if there was no love in it. It is love only that enables us to sacrifice for our loved ones - to revel in their happiness and be sad when they are in pain. Just think what the relationship between parents and their children would be, if there was no love in it. Would the mother still be willing to give her all, for her child? In other worlds, there never has been, not there will be, any meaningful relationship without love in it. It is the 'be all and end all' of our existence.