Our "I" is Self-Deceiving

It is common worldly knowledge that by believing untrue information to be true we fall into confusion and are harmed. Similarly, by believing phenomena to be inherently existent when in fact they are not inherently existent, we are also harmed. For example, with respect to the different ways in which there can be a consciousness of 'I', there is a definite difference between the way the 'I' is apprehended when desire, hatred, pride and so forth are generated based on this 'I', and the way the 'I' is apprehended when we are relaxed without any of those attitudes being manifest.
Similarly, there is the mere consciousness that apprehends an article in a store before we buy it, and there is the consciousness apprehending that article after it has been bought, when it is adhered to as 'mine' and grasped with attachment. Both these consciousnesses have the same object, and in both cases the mode of appearance of the article is the appearance of it as inherently existent. However, there is the difference of the presence or absence of our adhering to it as inherently or independently existent.
...a consciousness conceiving inherent existence precedes any bad consciousness, leading it on by the nose, and also accompanies, or aids, many other bad consciousnesses as well. Thus, if there were no ignorance conceiving inherent existence, then there would be no chance for desire, hatred and so forth to be generated.
--from The Buddhism of Tibet by the Dalai Lama, translated and edited by Jeffrey Hopkins,

Who Are We?

As human beings we are deeply insecure and we do not know who we truly are. Of course this problem does not show on the surface of our lives. We are always telling ourselves who we are, based on this notion that we are separate from everything else. This sense that "I am separate" is the ground of our sense of self. It is reinforced by various false identities that we cling to, notions that "I am this" or "I am that." Whatever beliefs we have about ourselves are just another extension. Most of the time when we look around, we immediately see that our surroundings are validating these false identities. For this very reason, it is a challenging endeavor to deconstruct this illusion of self.
Every time we look into our mirror we might have some thought about ourselves. Each of these thoughts adds up. They become the conceptual bricks we use to keep building this illusory castle of self. Yet, there is a suspicion that this notion of self might be very fragile and transient, and this thought is silently lurking somewhere in our consciousness. Most of the time this suspicion is not brought into the light of awareness, but if it is, some deep, inner wisdom will arise without choice.
Our suspicion of the fragility of this false notion of self can go in one of two directions. In general it becomes a source of fear, anxiety, and insecurity. We often see people who are fearful and overly defensive when it comes to their own identity. We ourselves tend to become fearful if our identity is threatened. But at other times the suspicion can go another way. When that happens, it can be a life-changing revelation that can lead us to the realization of the highest level of truth. This idea is not some new, lofty theory. It is timeless wisdom that has been realized by many people in human history. Buddha taught this wisdom, and in his tradition it is called anatman or "no self." Anatman, or "no self," is the term used to mean that one has seen through this false sense of self. One has seen that this false sense of self is merely an identification with one's roles in life. It is just a mask, not the truth.
--from No Self, No Problem by Anam Thubten,

Understanding "Emptiness"

By understanding emptiness, by clearly perceiving the empty nature of all phenomena, including ourselves, we can liberate ourselves from negative emotions, and thus from the creation of unwholesome karma and the power of the internal enemy. Through this process, we can begin to undo the harm we've caused by our grasping, and the derivative strong emotions to which it gives rise. The moment we begin to develop insight into the empty nature of self and all reality, the process of releasing our deluded grasp begins. At the moment of our first insight into the empty nature of self and reality, we start to break free of the enslavement of ignorance and the attack of the internal enemy. By reducing our grasping, we start to undo the causal chain of unenlightened existence. By undermining self-grasping ignorance, the first link of dependent origination, you prevent the arising of the second link, and ultimately become free of the endless cycle of suffering lifetimes.
But what does all this mean exactly? If we arrive at the knowledge that the self at which we grasp is empty, we may imagine this means that we as individuals with personal identities do not exist. But of course this is not the case--our own personal experiences demonstrate that as subjects and agents of our own lives, we certainly exist. So how, then, do we understand the content of this insight into absence of self? What follows from this insight? We must be very clear that 'only the self that is being grasped as intrinsically real' needs to be negated. The self as a conventional phenomenon is not rejected. This is a crucial aspect of the Buddha's teachings on emptiness.

The Function Of Our Consciousness

Knowing or understanding is the function of consciousness.... That which possesses the function of knowing is consciousness. 
      Consciousnesses vary in the scope of their knowledge and in their intensity or sharpness. An obvious example is the consciousness of a human being, compared to an animal's consciousness. The human being's perception is much broader and it understands a much greater variety of objects. The consciousnesses of human beings vary with education and experience--the more educated you are and the more experience you have, the broader your consciousness.
      Knowledge and understanding develop on the basis of a consciousness that has the ability to perceive its objects. When the necessary conditions are met, the mind's ability to perceive increases, the scope of its objects of knowledge expands, and understanding deepens. In this way the mind can develop its full potential. Omniscience is the full consummation, or perfection, of the mind's ability to perceive objects.