In order to make it through our lives, we have to believe some things without much analysis. For example, when I "go" at a green light, I have to assume the competence and the attentiveness of the driver who has stopped at the red light in the other direction, because if I thought about it too much, I would find the act of driving impossible. Some other more philosophical beliefs, it can be argued, are best unexamined. Love, faith, and belief in one's own abilities are concepts that people would generally rather take as given. Doing so makes it possible for us to interact with others, and helps us go through our lives without being paralyzed by self-doubt.
But still, examining these beliefs has certain advantages. Love is supposedly unconditional, but thinking about what this looks like in practice may allow people to reflect on how love guides their actions. Does love, for example, mean that a parent cannot take a hard line in dealing with their children? Does faith mean uncritically accepting what church leaders say, or rejecting science when it does not comport with religious belief? Many people may find that their beliefs are strengthened through this kind of examination.
The major disadvantage of this is that it leads to blind certainty and even to what might be called bigotry. If we simply believe things without thinking about them, we are closing our minds. We are rejecting the possibility of change or growth in terms of our ideas.
The major advantage of unexamined belief is that it can in some way humanize us. If we only believe things for which we have proof, we lose some of the emotional side of us that makes us human. For example, I cannot prove that such a thing as love exists. But if I did not believe that love can exist, how would I be able to fall in love and how would I be able to love my children? These things are part of human existence and cannot exist if we insist on objective proof for everything.