Psychoanalytic theory of selfishness

 One of the main plus points of studying Psychology is that it broadens your perspective and makes you realize that there are all kinds of people in the world- the friendly ones, the shy, the bold, the hyper. In recent times, i have been trying to figure out what is it in a person that moulds them to be who they are. Freud's theory worked wonders in helping me with this, (to some degree) that the outward behavior is influenced by the unconscious. So, it is something in the environment or some event that has taken place in the life of the individual that makes him acquire certain distinct characteristics. For example, a girl who was physically abused during childhood, tends to develop hatred against men. But this does not explain selfishness wherein people talk about a certain event just to make another person feel terrible about it, or to rub it in their face. Guess it makes them feel good about it, but what ever happened to the conscience of these people? Do they not feel guilty for going that? Or don't they know what they are doing?

What i haven't been able to figure out so far is what exactly makes a person be selfish? Being possessive is one thing, but there are people who talk to you only when they need your help, or else, your existence does not matter to them; they are with you as long as they feel they need you and the minute they meet someone new or someone who they feel are better than you, they do not even give you a glance. None of the theories on personality have been helpful in stating a reason for this; it cant be an acquired trait because it does not classify as a basic feeling so how could one acquire it or learn it from the environment unless, a child is taught to put his needs first and not give a thought about anything else? I am sure no parent would invoke that feeling in their child. So, it's not a learnt trait, does not fit the social theory, is definitely is not explained in the Humanistic Approach, then what is it. I think i just confused myself. :|

Apparently, I happen to be blessed in meeting a good lot of such people and since i am the only one who seems to see this trait of theirs, i am getting bored. I need a variation, a different trait to break my head upon. Selfishness is getting plain monotonous and annoying.