We all have an ego, it is not a state of self love or adoration (that is narcissism) but a function of the human psyche that provides orientation for our sense of self in relation to the environment.
We need an ego, it helps as plan, execute appropriate action, know who we are and maintain our self image. The ego is a stucture necessary to be in this world. People who have lost their mind (so to speak) who's ego has temporarily or ongoingly disintegrated are unable to function. This could be due to insanity or a spiritual crisis. By and large most of us maintain a sense of identity and egoic functionality to lead regular lives in the world. Ego is * Sense of self and identity based on past experience * The planning and action taking function of the human mind * Different roles or parts of self that emerge in different situations * Conditioned (programmed) over time and sometimes corrected in new experiences * Defensive of its own structure and survival
Why work on your ego? Basically the ego limits our freedom. The ego's sense of who you are is based on past experience so your resulting ego-identity is really a conglomeration of past experiences and what other people told you you were. IT IS NOT WHO YOU TRULY ARE. The ego fights to maintain your identity and its status quo, ego resists change and any threat to its established sense of the world. The ego (unless dysfunctional) is your fear. Its not your fight or flight system but it informs why you should be afraid. The ego, especially a branch of the ego called the superego, will tell you that change of any kind is a bad idea. An inflexible neurotic ego will fight to maintain the status quo and prevent you from growing.
Depending on the overall health and flexibility of the ego this can verge toward narcissism - a neurotic way of being where ones sense of self importance overrides empathy for others and senstivity to insults and slights is heightened. People can suffer from grandiose narcissism where they believe they are entitled to more than others, self-depreciating narcissism where they reveal in the idea that they are far more despicable than others, and pathological or malignant narcissism where an individual actively uses and abuses others as they are seen as mere objects to the narcissist.
We all have a degree of narcissism as we all indulge in thoughts and obsessions of unrealistic self importance. We all have fragmented egos where one part of us can do something in contradiction with another part of self. If you want a basic understanding of yourself, list all the things you count as your values then look at all the parts that contradict or cancel the other out. We all have a superego and we all have a more instinctual part of ego (that Frued called the ID) that battles with the superego. Hence the internal conflicts that take up so much of your energy and time.
This is the part of ego that causes the most trouble, or constriction. The super ego was Frueds terms for the over self, the inner critic some people call it. Its the constellation of all voices of authority and parents all molded into a giant inner stick we use to beat ourselves with. The super ego is partly conscience. However, conscience is a healthy form of social guilt that motivates us to do the right thing by our fellow humans. Our superego is a psychic introject that will keep us awake at night replaying what we should have said and done during that event that happened days ago. The superego is our inner judge, jury and witness, like a police officer on duty all the time (except when our id breaks out and instinctual impulses burst out). In the most sensitive and conscientiously minded the superego can be a terrible inner tyrant. The superego also gets projected out onto others in the world, this is when you feel judged or reactive in the face of someone who may not be doing very much at all as far as someone else is concerned.
Everyone has a shadow as part of the ego-self. The egoic personality or persona is fragmented into various aspects that are either accepted as part of the conscious identity or rejected and disowned. Hence the shadow is the place we put all the things we don't like and can't accept. If we value being social the shadow will contain our hostility and desire to isolate, if anger was punished in us and we were praised for being quiet we may have repressed our natural agreession and feel pride in our ability to keep our mouth shut. In general, we can look at what we value and see the opposite as sitting in the shadow. As the ego exists in a world of duality and polarities we identify with what we value or was acceptable in us. It forms our self image, who we think we are. But in truth, we are everything as each polarity must contain its opposite. Light can't exist without dark, we can't appreciate the warmth of the sun as much when we have felt the hard cold. All aspects of the personality has an opposite in existence in us in our shadow and the shadow can be light or dark, meaning, we may reject our vulnerability so it goes into a light shadow while we present a tough hard exterior. Conversely, all of our darkness in hatred and loathing is repressed in the shadow while we identify solely as a kind loving person. It is important to acknowledge that as a human we are all things. No one is perfect, no one gains anything from self-rejection and a huge amount of our resources and vital energy is lost in the act of disovowing our shadow .